Final Flashcards

Question

Pharyngeal tonsil

Answer 1

The submucosa of nasopharynx contains a collection of lymphoid tissue called the pharyngeal tonsil. Enlarged pharyngeal tonsils constitute the clinical condition known as adenoids. The lateral wall contains the opening of the pharyngotympanic (auditory) tube.

Answer 2

The salpingopharyngeus muscle attaches to the lower margin of the pharyngotympanic tube and produces a vertical salpingopharyngeal fold.

Answer 3

extends from the soft palate to the upper border of the epiglottis, and opens anteriorly into the oral cavity. The floor is formed by the posterior third of the tongue and the interval between the tongue and the epiglottis. The anterolateral walls of the oropharynx are formed by elevations of mucosa known as palatine arches (tonsillar pillars).

Answer 4

extends from the epiglottis to the lower border of the cricoid cartilage. Anteriorly, it opens into the laryngeal inlet, and the back of the arytenoid and cricoid cartilages. The piriform recesses lie on either side of the laryngeal inlet and guide food into the esophagus. The superior and inferior laryngeal vessels, and internal and recurrent laryngeal nerves lie just under the mucosa of these recesses and can be damaged easily here. The laryngopharynx continues inferiorly as the esophagus.

Answer 5

walls of the pharynx are covered by mucous membrane that is continuous with that of the nasal and oral cavities, larynx, auditory tubes, middle ear and esophagus.

Answer 6

muscle originates from the fibrous pterygomandibular raphe, mandible and lateral pterygoid plate.

Answer 7

Originates from the hyoid bone

Answer 8

muscle originates from the thyroid and cricoid cartilages.

Answer 9

muscle originates from the hard palate and inserts into the side of the pharynx and the thyroid cartilage. It functions to elevate the pharynx and larynx for swallowing and speaking. It is innervated by the vagus nerve (CN X).

Answer 10

originates from the pharyngotympanic tube and terminates by blending with the palatopharyngeus muscle. It has a similar function to the palatopharyngeus muscle and is also innervated by CN X.

Answer 11

muscle takes origin from the styloid process of the temporal bone and inserts onto the pharynx and thyroid cartilage. It shortens and widens the pharynx during swallowing and speaking. It is innervated by the glossopharyngeal nerve (CN IX). In fact, the stylopharyngeus muscle is the only muscle receiving innervation by the motor component of CN IX.

Answer 12

Pharyngotympanic tube Levator veli palatini muscle

Answer 13

Stylopharyngeus muscle Glossopharyngeal nerve

Answer 14

Internal laryngeal n

Answer 15

Recurrent laryngeal n

Answer 16

Motor—CN X; except for stylopharyngeus, which is innervated by CN IX 2. Sensory—nasopharynx by CN V2; oropharynx and hypopharynx by CN IX 3. These fibers mingle together in the pharyngeal plexus.

Answer 17

After food is chewed and mixed with saliva, it is formed into a bolus on the dorsum of the tongue and pushed upward and backward against the underside of the hard palate. Contractions of the palatoglossus muscles then squeeze the bolus backwards through the oropharyngeal isthmus into the oropharynx.

Answer 18

The nasopharynx is now separated from the oropharynx by the actions of tensor veli palatini muscle (tensing) and levator veli palatini muscle (raising) on the soft palate, and by the upper fibers of the superior constrictor muscles pulling the posterior pharyngeal wall forward. Also, the palatopharyngeal arches are pulled into opposition The larynx and laryngopharynx are elevated toward the epiglottis and the laryngeal opening is narrowed. The bolus moves around the epiglottis and the laryngeal opening to the lower part of the pharynx by gravity and successive contractions of the superior, middle, and inferior pharyngeal constrictor muscles. The cricopharyngeal sphincter relaxes and the bolus enters the esophagus. Here, peristaltic contractions push the bolus into the stomach.

Answer 19

orbital part—encircles the orbit; used for forceful closure ii. palpebral part—within the eyelids; used for gentle closure to protect the cornea and spread tears

Answer 20

encircles the mouth as a sphincter; located within the upper and lower lips. It controls most lip movements and is responsible for actions like eating, drinking, whistling, and kissing. It also helps with speech and oral competence.

Answer 21

from the zygomatic bone to the orbicularis oris muscle. It raises the corners of the mouth during smiling.

Answer 22

- assists zygomaticus major in smiling, speech and chewing

Answer 23

two bellies connected by an aponeurosis

Answer 24

from the alveolar processes of the maxilla and mandible, and pterygomandibular raphe, to fuse with the orbicularis oris muscle. It maintains the tightness of the cheeks and presses them against the teeth during chewing

Answer 25

1. All muscles of facial expression are innervated by terminal branches of the facial nerve (CN VII). 2. Clinical Condition: Bell’s Palsy Damage to CN VII within the facial canal of the temporal bone. Causes weakness or paralysis of the muscles of facial expression on the ipsilateral side. 3. Sensory innervation is provided by all 3 divisions of the trigeminal nerve (CN V): a. CN V1—supraorbital and supratrochlear nerves b. CN V2—infraorbital nerve c. CN V3—mental nerve

Answer 26

1. 2. Large salivary gland anterior to the ear and superficial to ramus of the mandible. Secretes a serous fluid containing α-amylase, lysozyme, IgA and several other biologically active substances. 3. 4. 5. Inflammation causes enlargement in mumps. Branches of the facial nerve emerge from the gland. The parotid duct crosses the masseter muscle, pierces the buccinator muscle, and empties into the oral cavity.

Answer 27

E. Masseter muscle 1. Origin—zygomatic arch 2. Insertion—mandible, lateral surface of the angle and lower ramus 3. Innervation—CN V3 (mandibular division of the trigeminal nerve) 4. Action—elevates the mandible, allowing forceful closure of the mouth; muscle of mastication

Answer 28

Blood supply—mainly from branches of the facial artery and superficial temporal branches of the external carotid artery.

Answer 29

1) as a sphincter at the air inlet passage, 2) to maintain the patency of the airway, and 3) in voice production. It allows air to pass into the trachea and food to pass into the esophagus. It is related posteriorly to the bodies of vertebrae C3-C6 and laterally to the carotid sheaths.

Answer 30

—has two plates (laminae), which meet in the median plane as the laryngeal prominence (Adam's apple). It also has superior and inferior horns, attached to the hyoid bone and cricoid cartilage, respectively. It is open posteriorly.

Answer 31

shaped like a signet ring, with a broad lamina posteriorly and a narrow arch anteriorly. The lateral surface has a facet for articulation with the inferior horn of the thyroid cartilage. The upper surface of the lamina has an articulation with the base of the arytenoid cartilage. It is the only cartilage to completely encircle the airway

Answer 32

pyramidal cartilage located on the lateral part of the upper border of the cricoid lamina. It has a vocal process that projects anteriorly and gives attachment to the vocal ligament, and a muscular process that projects laterally for the attachment of the posterior and lateral cricoarytenoid muscles.

Answer 33

soft leaf-shaped cartilage behind the hyoid bone and root of the tongue, and in front of the laryngeal inlet. The front is attached to the hyoid bone and the stalk is attached to the thyroid cartilage. The sides are connected to the arytenoid cartilages by the aryepiglottic folds

Answer 34

suspends larynx from hyoid bone. It is pierced by the superior laryngeal artery and vein, and the internal laryngeal nerve.

Answer 35

—thin sheet of connective tissue that extends between the lateral portions of the arytenoid and epiglottic cartilages. Its free inferior border forms the paired vestibular ligaments, which, when covered by mucosa, form the vestibular (false vocal) folds. Its superior edges form the aryepiglottic folds.

Answer 36

its anterior portion connects the cricoid and thyroid cartilages. Its thickened free superior border forms the vocal ligament, with an attachment posteriorly to the vocal process of the arytenoid cartilage and anteriorly to the back of the angle of the thyroid cartilage.

Answer 37

Bounded in front by the epiglottis, laterally by the aryepiglottic folds, and posteriorly by the mucosa between the arytenoids

Answer 38

—from inlet to vestibular folds

Answer 39

from vocal ligament to the lower border of the cricoid cartilage

Answer 40

vibrate to produce sound. Their free margins are oriented anterior to posterior. Laryngeal muscles adjust the tension and degree of approximation of the vocal folds.

Answer 41

the opening between the vocal folds

Answer 42

Rima glottidis plus the vocal folds

Answer 43

Provide protection to the glottis and the infraglottic cavity. The ventricle contains mucus-secreting glands that lubricate the vocal folds.

Answer 44

elevators—suprahyoid muscles and stylopharyngeus, salpingopharyngeus, palatopharyngeus b. depressors—infrahyoid (strap) muscles

Answer 45

origin—muscular process of arytenoid ii. insertion—apex of opposite arytenoid, then continues into aryepiglottic folds as the aryepiglottic muscle iii. action—adducts arytenoids and draws them towards the epiglottis; adducts aryepiglottic folds

Answer 46

origin—back and medial surface of arytenoid ii. insertion—back and medial side of opposite arytenoid iii. action—adducts arytenoid cartilages to close the posterior part of the rima glottidis

Answer 47

Motor—all intrinsic muscles, except cricothyroid, are innervated by the recurrent (inferior) laryngeal nerve. Cricothyroid is innervated by the external laryngeal nerve. Sensory—the mucosa from the vocal folds upward is by the internal laryngeal nerve; the mucosa below the vocal folds is by the recurrent laryngeal nerve BLOOD SUPPLY 1. 2. Superior laryngeal artery, from the superior thyroid artery Inferior laryngeal artery, from the inferior thyroid artery

Answer 48

the larynx is elevated by the suprahyoid muscles and other elevators. The inlet is narrowed by the oblique arytenoid and aryepiglottic muscles. Food passes laterally down the piriform recesses into the esophagus.

Answer 49

—the rima glottidis is closed by the sphincters after a deep breath. The expiratory muscles are contracted to increase intrathoracic pressure, then the rima glottidis is opened rapidly.

Answer 50

the rima glottidis is closed after deep breath. Due to air trapped in lungs, the diaphragm cannot move upwards when the abdominal muscles are contracted, so pressure is transmitted to the pelvis and abdomen.

Answer 51

vocal ligaments adducted. Expired air vibrates the vocal ligaments with a frequency depending on length and tension. The quality of the voice depends on resonation by the pharynx, mouth, and paranasal sinuses. For high tones, the entire larynx is elevated; for low tones, it is depressed.

Answer 52

supporting layer, consisting of a dense connective tissue layer, the sclera posteriorly, and a transparent cornea anteriorly. The sclera is continuous with the dura surrounding the optic nerve at the posterior pole of the eyeball. The cornea is avascular, but richly innervated with sensory nerves from CN V1.

Answer 53

from posterior to anterior, consists of the choroid, ciliary body, and iris.

Answer 54

between the sclera and retina; highly vascularized to supply the adjacent retina.

Answer 55

contains ciliary processes anteriorly, which secrete aqueous humor into the posterior chamber of the eye (posterior to the iris). The ciliary body also has smooth muscle fibers, which draw the ciliary body toward the lens. Because the lens is suspended from the ciliary body by suspensory ligaments, this action relaxes the suspensory ligaments, allowing the natural elasticity of the lens capsule to cause the lens to become more convex, thus increasing its focusing ability for near objects. The ciliary muscle is innervated by parasympathetic nerve fibers in CN III.

Answer 56

contractile diaphragm that regulates the amount of light entering the pupil and affects focusing depth by altering the size of the pupil. Radially oriented smooth muscle—the dilator pupillae—dilates the pupil, and is innervated by sympathetic nerve fibers from the superior cervical ganglion. Circularly oriented muscle fibers—the sphincter pupillae—constrict the pupil, and are innervated by parasympathetic fibers in CN III.

Answer 57

a circular region medial to the posterior pole of the retina, where the optic nerve leaves the eyeball

Answer 58

just lateral to the optic disc Fovea centralis—central depressed part of macula lutea; the area of highest visual acuity

Answer 59

continuations of the outer pigment cell layer of the retina over the inner surface of the ciliary body and iris; not light sensitive

Answer 60

separation between the pigment epithelium and the neural layers of the neural retina.

Answer 61

Provides most refraction, but is fixed

Answer 62

flows from the posterior chamber through the pupil into the anterior chamber, and is drained into the venous system at the scleral venous sinus (canal of Schlemm) at the iridocorneal angle

Answer 63

flexible, biconvex; transparent and avascular

Answer 64

transparent gelatinous structure filling the space between the lens and the retina; forms the posterior 4/5 of the eyeball

Answer 65

thin, vascular, transparent mucous membrane covering the sclera (bulbar conjunctiva) and the inner surfaces of the eyelids (palpebral conjunctiva).

Answer 66

1. Branches of ophthalmic artery, from the internal carotid artery, are the primary blood supply to the eye and the orbit. 2. Venous drainage is via the ophthalmic veins, which can drain into the facial vein, or into the cavernous sinus. Beware infections in the face or orbit.

Answer 67

—tears produced by the lacrimal gland in the superolateral corner of the orbit, flow across the cornea, drain into the lacrimal punctum at the medial end of the lids, through the lacrimal canaliculus and lacrimal sac into the nasolacrimal duct, which empties into the nasal cavity

Answer 68

—both insert posterior to the equator of the eyeball (i.e., behind the pivot point). Because of this, the superior oblique depresses the eye and the inferior oblique elevates the eye. Also, because of their relationship to the vertical axis of the eyeball, both muscles can aid in abduction.

Answer 69

superior and inferior recti muscles are most effective when the eye is abducted; the superior and inferior obliques are most effective when the eye is adducted.

Answer 70

All the extraocular muscles are innervated by CN III, except: 1. 2. Lateral rectus, innervated by CN VI Superior oblique, innervated by CN IV

Answer 71

No pronation or supination takes place between the bones of the leg.

Answer 72

longest and heaviest bone in the body. Proximally it has a head, which forms the ball of the hip joint. Just distal to the head, the neck of the femur makes an abrupt angle. The long femoral neck allows increased mobility, but is subjected to much strain. At the junction of the neck and shaft are two large prominences called the greater trochanter and the lesser trochanter. These are important sites of muscle attachment. The long shaft of the femur is marked on its posterior surface by a rough line of muscle attachment called the linea aspera (rough line). At the knee joint, the femur broadens into two condyles. Just proximal to the medial femoral condyle is a site of muscle attachment called the adductor tubercle.

Answer 73

(kneecap) is a bone within the tendon of the quadriceps muscle—a sesamoid bone—that articulates with the anterior surface of the femur at the knee joint.

Answer 74

usually refers to a fracture in the neck of the femur, between the head and the greater trochanter.

Answer 75

bounded superiorly by the iliac crest and inferiorly by the gluteal fold. The prominence formed by the gluteus maximus and gluteus medius muscles, together with superficial fascia, form the buttocks. The ischial tuberosity can be palpated deep to the gluteus maximus muscle.

Answer 76

principal extensor of the thigh. Its origin is from the ilium, sacrum, and the sacrotuberous ligament. It inserts on the iliotibial tract as well as on the femur. It is innervated by the inferior gluteal nerve, which enters the gluteal region through the greater sciatic foramen.

Answer 77

broad origin from the external surface of the ilium and inserts on the greater trochanter of the femur. It plays an important role in keeping the pelvis from tilting from side to side while walking. It is located superficially in the superior and lateral part of the buttocks, but is covered by the gluteus maximus elsewhere. The gluteus medius (not the gluteus maximus) muscle is frequently the site of intramuscular injections. The gluteus medius muscle is innervated by the superior gluteal nerve. If this nerve is damaged, the patient will exhibit a positive Trendelenburg Sign—the right hip drops when the right foot is lifted off the ground, indicating damage to the left superior gluteal nerve (or vice versa).

Answer 78

too, is innervated by the superior gluteal nerve. The gluteus minimus muscle assists the gluteus medius muscle in stabilizing the pelvis and abduction of the thigh. It also acts as a medial (internal) rotator of the thigh.

Answer 79

exits the pelvis via the greater sciatic foramen and inserts on the greater trochanter of the femur. The piriformis muscle is a landmark in the gluteal region: nerves and vessels are referred to as “superior” or “inferior” depending on their relation to the piriformis muscle (e.g., the inferior gluteal nerve is inferior to the piriformis muscle).

Answer 80

enters the gluteal region via the lesser sciatic foramen and inserts on the greater trochanter of the femur. Frequently only the tendon of the obturator internus is seen in the gluteal region; the muscle belly lies completely within the pelvis.

Answer 81

Two small muscles take origin from the margins of the lesser sciatic foramen and insert on the tendon of the obturator internus muscle

Answer 82

seen spanning the hip joint from the ischial tuberosity to the intertrochanteric crest of the femur. In addition to lateral rotation, all of these muscles help stabilize the head of the femur in the acetabulum.

Answer 83

largest nerve in the body. It is really two nerves—the tibial nerve and the common fibular (peroneal) nerve—wrapped together in a common connective tissue sheath. It enters the gluteal region via the greater sciatic foramen and passes inferiorly deep to the gluteus maximus. It does not supply muscles in the gluteal region, but instead innervates the muscles of the posterior thigh, leg, and foot. The sciatic nerve usually splits into the tibial nerve and common fibular nerve in the thigh, but sometimes this split is observed in the gluteal region. Damage to the sciatic nerve is potentially extremely debilitating. This is one reason for targeting intramuscular injections into the gluteus medius muscle, away from the sciatic nerve. Herniated lumbar intervertebral disks can irritate the lower lumbar or S1 nerve roots of the sciatic nerve, resulting in sciatica pain radiating down the posterior thigh and leg.

Answer 84

3. Trochanteric bursitis- common in female runners as the ITB snaps over the greater trochanter Iliotibial band syndrome- inflammation of the ITB as it slides over the lateral epicondyle Piriformis syndrome- piriformis muscle presses on the sciatic nerve, causing pain, tingling, or numbness in the buttocks and down the back of the leg. The pain may feel like burning or shooting down the thigh, numbness in the buttocks, tingling along the sciatic nerve, or pain that worsens after sitting, climbing stairs, walking, or running

Answer 85

3. Trochanteric bursitis- common in female runners as the ITB snaps over the greater trochanter Iliotibial band syndrome- inflammation of the ITB as it slides over the lateral epicondyle Piriformis syndrome- piriformis muscle presses on the sciatic nerve, causing pain, tingling, or numbness in the buttocks and down the back of the leg. The pain may feel like burning or shooting down the thigh, numbness in the buttocks, tingling along the sciatic nerve, or pain that worsens after sitting, climbing stairs, walking, or running

Answer 86

iliofemoral ligament is found on the anterior part of the joint; it prevents overextension, and helps maintain erect posture by resisting the hip extension caused by bearing weight.

Answer 87

The ischiofemoral ligament is found posteriorly; it also limits extension

Answer 88

. The pubofemoral ligament is found inferiorly; it prevents excessive abduction.

Answer 89

Most of the blood supply of the head of the femur comes from the medial and lateral femoral circumflex vessels, branches of the deep femoral artery or the femoral artery. These branches can be injured when the neck of the femur is fractured leading to aseptic necrosis of the head of the femur.

Answer 90

There are many clinical conditions that can result in degeneration of the hip joint, including trauma, osteoarthritis, and rheumatoid arthritis. These conditions may be severe enough to necessitate an artificial hip replacement.

Answer 91

tibia is strong and weight bearing. It articulates with the femur proximally to form the knee joint, and with the talus of the foot distally to form the ankle joint Most frequently fractured long bone Because it is located so close to the skin, these fractures are often compound fractures.

Answer 92

. In contrast, the fibula, which runs on the lateral side of the leg, is not weight bearing, and is instead a site of muscle attachment. Between the tibia and fibula runs a strong interosseous membrane. The fibula is attached to the tibia both proximally and distally by strong ligaments. The fibula does not articulate with the femur, but it does take part in the formation of the ankle joint.

Answer 93

huge muscle found in the thigh that extends the leg—the quadriceps femoris muscle

Answer 94

deep fascia is called the fascia lata in the thigh, and the crural fascia in the leg. Along the lateral aspect of the thigh, the fibers of the fascia lata are oriented vertically. This tract of fascia, which represents part of the insertion of muscles found in the hip onto the lateral aspect of the knee and leg, is called the iliotibial tract or iliotibial band (ITB). The fascia lata and crural fascia help to pump venous blood out of the lower limb. When the muscles of the lower limb contract, these fasciae prevent them from bulging outward, and force them to compress thin-walled veins. The fascia surrounding the lower limb also helps the various muscles to work more efficiently in unison as we walk and run.

Answer 95

great saphenous vein drains blood from the medial aspect of the foot, leg, and thigh, and returns this blood to the femoral vein by passing through an opening in the fascia lata of the proximal thigh, called the saphenous opening. “Saphenous” means obvious, and the great saphenous vein is large and constant. In almost everyone, the great saphenous vein can be found running just anterior to the medial malleolus at the ankle.

Answer 96

branch of the femoral nerve. It follows the greater saphenous vein (hence the name) in the leg and ankle, and innervates the skin over the medial leg, ankle, and foot.

Answer 97

innervates most of the dorsum of the foot.

Answer 98

innervates the cleft between the big toe and the second toe.

Answer 99

comes from both the tibial and common fibular nerves, and supplies the lateral side of the ankle and foot. It is large, constant, superficial and redundant. This makes it ideal for a source of nerve sheath during reconstructive surgery

Answer 100

comes from both the tibial and common fibular nerves, and supplies the lateral side of the ankle and foot. It is large, constant, superficial and redundant. This makes it ideal for a source of nerve sheath during reconstructive surgery

Answer 101

Extend leg and flex thigh Nerve; femoral nerve Blood; femoral a

Answer 102

Adductor thigh Nerve; obturator n Blood; obturator a

Answer 103

Flex leg and extend thigh Nerve; sciatic nerve Blood; perforating branches of the deep femoral a

Answer 104

if the leg extends in response to the sudden stretching of the patellar ligament, the femoral nerve (L2-L4) and its reflex arc are intact (“L2, L3, L4 kick the foot off the floor”)

Answer 105

has four heads of origin. These heads insert onto the tibial tuberosity via the patella and the patellar ligament rectus femoris, vastus lateralis, vastus medialis, and vastus intermedius. The rectus femoris takes origin from the anterior inferior iliac spine. Thus, this head crosses two joints, the hip joint and the knee joint. It will flex the hip and extend the knee. The other three heads take origin from the femur so they can only extend the knee.

Answer 106

a long (the longest muscle in the body) strap-like muscle that runs obliquely across the thigh from the anterior superior iliac spine to the medial part of the tibia. Its circuitous path means that it flexes, abducts, and laterally rotates the hip, and also flexes the knee.

Answer 107

iliopsoas muscle is really two muscles: the psoas major muscle and the iliacus muscle. These muscles take origin in the abdomen from the iliac fossa (iliacus) and from the lumbar vertebrae (psoas major), and insert together on the lesser trochanter of the femur. They are the primary flexors of the hip joint. The iliacus muscle is usually innervated by the femoral nerve, and the psoas major is innervated by branches of the lumbar plexus

Answer 108

small muscle that runs from the superior pubic ramus to the pectineal line on the posterior femur, just distal to the lesser trochanter. It flexes and adducts the thigh. It is usually innervated by the femoral nerve, but can be innervated by the obturator nerve. Note from its location, actions, and potentially unusual innervation, that it may be placed in either the anterior compartment or the medial compartment—it lies on the border of these compartments in the proximal thigh.

Answer 109

tensor fasciae latae muscle lies on the border of two compartments, and shares features of both. It lies “between” the anterior compartment and the gluteal region. It is found on the lateral aspect of the thigh near the iliac crest. It takes origin from the iliac crest and the anterior superior iliac spine, and it inserts via the iliotibial tract on the lateral side of the head of the tibia. Its role is controversial, but it probably helps to steady the trunk over the thigh when standing. It can also help flex and abduct the thigh at the hip joint. It is innervated by one of the major nerves of the gluteal region—the superior gluteal nerve.

Answer 110

1. Sartorius muscle flexes the knee 2. Psoas major muscle is not innervated by the femoral nerve 3. Pectineus and tensor fasciae latae muscles share features of two compartments

Answer 111

gracilis is a long, strap-like muscle that runs from the pubis to the medial part of the tibia. It is primarily an adductor of the thigh at the hip, but it can also flex the leg at the knee.

Answer 112

muscle is found on the external surface of the membrane that covers the obturator foramen. It inserts on the femur in the gluteal region, and like most of the small muscles of the gluteal region, it helps to rotate the thigh laterally.

Answer 113

triangular region bounded superiorly by the inguinal ligament, laterally by the sartorius muscle, and medially by the medial margin of the adductor longus muscle. Its floor is composed of the iliopsoas, pectineus, and adductor longus muscles

Answer 114

sleeve of abdominal fascia that extends for a few centimeters into the femoral triangle. It surrounds the femoral artery, femoral vein, and lymphatics within the femoral canal, and allows smooth movement of the femoral vessels beneath the inguinal ligament.

Answer 115

One of its branches is the saphenous nerve, which travels with the femoral artery in the adductor canal, then becomes a superficial cutaneous nerve along the medial aspect of the leg, ankle, and foot

Answer 116

continuation of the external iliac artery) is the principal blood supply to the lower limb. In the femoral triangle it gives rise to the deep femoral artery, which supplies the posterior compartment of the thigh via perforating branches, and gives off the medial and lateral femoral circumflex arteries to the head and neck of the femur. The femoral artery continues inferiorly from the apex of the femoral triangle deep to the sartorius muscle toward the knee. It eventually passes along the posterior (flexor) side of the knee as the popliteal artery.

Answer 117

semitendinosus is about half (semi) muscle belly and half cord-like tendon. The semimembranosus has a broad sheet-like tendon (like a membrane), and the biceps femoris is a two-headed thigh muscle. Each hamstring muscle takes origin from the ischial tuberosity and inserts in the proximal part of the leg (the semitendinosus and semimembranosus medially on the tibia, and the biceps femoris laterally on the head of the fibula). All of these muscles extend the thigh and flex the leg, and are innervated by the tibial nerve

Answer 118

oddball. The smaller of the two heads of the biceps femoris muscle is not a hamstring. It takes origin from the shaft of the femur, and inserts together with the long head onto the head of the fibula. Thus, unlike the hamstrings, it acts only on the knee joint, and is innervated by the common fibular nerve.

Answer 119

modified hinge joint, permitting some rotation in addition to flexion and extension. The primary articulation is between the condyles of the femur and tibia. There is secondary articulation between the patella and the femur anterior to the joint.

Answer 120

from the anterior part of the intercondylar region of the tibia posteriorly to the femur. It prevents the hyperextension of the knee and limits anterior displacement of the tibia on the femur.

Answer 121

runs from the posterior part of the intercondylar region of the tibia anteriorly to the femur. It limits hyperflexion of the knee and posterior displacement of the tibia on the femur.

Answer 122

articular surfaces of the condyles of the tibia are deepened by two crescent-shaped rings of cartilage called the medial meniscus and the lateral meniscus. The menisci are anchored to the tibia. In addition, the medial meniscus is firmly attached to the medial collateral ligament and the joint capsule. If the knee is hit by a blow from the lateral side when the foot is anchored (a common football injury), the tibial collateral ligament can tear. This usually results in a tear of the medial meniscus as well, since the two are attached to one another. If the blow is severe, the anterior cruciate ligament may be torn as well.

Answer 123

roughly diamond shaped. Its boundaries are the biceps femoris muscle (superolaterally), the semimembranosus and semitendinosus muscles (superomedially), and the heads of the gastrocnemius muscle (inferolaterally and inferomedially). Within the popliteal fossa are fat, lymphatics, the small saphenous vein, the popliteal artery (the continuation of the femoral artery), the popliteal vein, and two major nerves: the tibial nerve and the common fibular nerve.

Answer 124

Somewhere near the neck of the fibula, it divides into the superficial fibular nerve and the deep fibular nerve. The former innervates the lateral compartment; the latter innervates the anterior compartment.

Answer 125

anterior compartment is found just lateral to the tibia (shin) in the leg. These muscles dorsiflex the ankle, invert the foot, and extend the toes. They are innervated by the deep fibular nerve, and their blood supply is from the anterior tibial artery. Shin splints result from the inflammation of these muscles, particularly the tibialis anterior.

Answer 126

the fibularis (peroneus) longus and fibularis (peroneus) brevis. They take origin from the fibula and one is longer than the other—hence the names. They both evert the foot, and are innervated by the superficial fibular nerve. Their blood supply comes from perforating branches of the fibular artery, which resides in the posterior compartment. The tendons of both of these muscles pass behind the lateral malleolus, so they also act as weak plantar flexors. Fibularis longus actually passes across the sole of the foot and helps maintain one of the arches of the foot, especially under extreme loads.

Answer 127

Superficial group: Gastrocnemius; Tibial nerve Plantarflexes ankle and flexes leg Soleus; Tibial nerve Plantarflexes ankle Plantaris; Tibial nerve Plantarflexes ankle and flexes leg Deep group: Popliteus; Tibial nerve Medially rotates tibia on femur to unlock knee at onset of flexion Tibialis posterior ; Tibial nerve Plantarflexes ankle and inverts foot Flexor hallucis longus; Tibial nerve Flexes big toe and plantarflexes ankle Flexor digitorum longus ; Tibial nerve Flexes toes 2-5 and plantarflexes ankle

Answer 128

ankle (talocrural) joint is a hinge joint, permitting dorsiflexion (lifting the foot dorsally) and plantarflexion (the action used to stand on our toes). It is formed from a socket (mortise) made by the medial malleolus of the tibia and the lateral malleolus of the fibula articulating with the talus. A very strong, triangular, medial collateral (deltoid) ligament reinforces the ankle joint.

Answer 129

the posterior talofibular ligament, anterior talofibular ligament, and the inferiorly placed calcaneofibular ligament. The latter two ligaments are prone to injury by excessive inversion. Excessive eversion usually results in fractured bone (the medial malleolus and the distal part of the shaft of the fibula), since the deltoid ligament is so strong.

Answer 130

actions of eversion (lifting the lateral aspect of the foot off the floor) and inversion (lifting the medial aspect of the foot off the floor) take place at the transverse tarsal joint and the subtalar joint.

Answer 131

give us spring in our step, and act like shock absorbers. They also lift the central part of the sole of the foot off the floor, which helps to prevent injury to the muscles, vessels, and nerves that are found in the sole Each foot has a longitudinal arch and a transverse arch. The longitudinal arch has a lateral part and a medial part. The medial longitudinal arch is the larger and more important.

Answer 132

1) the ligaments of the foot, 2) the shape of the bones of the foot (they are wedge-shaped, and help to support the arch like the stones in a stone archway), and 3) the tendons of the extrinsic muscles of the foot (especially the tendon of the fibularis longus muscle, which crosses the transverse arch)

Answer 133

Abductor hallucis -Medial plantar nerve ; Abduct and flex big toe Flexor digitorum brevis - Medial plantar nerve; Flex toes 2-5 (homologous to FDS in the hand) Abductor digiti minimi - Lateral plantar nerve; Abduct little toe

Answer 134

Quadratus platae - lateral plantar nerve - Adjusts the pull of the flexor digitorum longus and flexes toes

Answer 135

Abduct and adduct toes (prevent toes from spreading when the foot is bearing weight) Lateral plantar nerve

Answer 136

both derived from the tibial nerve near the medial malleolus. The lateral plantar nerve innervates most of the intrinsic muscles of the foot as well as the skin over the little toe and the lateral side of the sole. In this regard, it is similar to the ulnar nerve in the hand. The medial plantar nerve innervates most of the intrinsic muscles of the foot that act on the big toe, the flexor digitorum brevis muscle (the homolog of the flexor digitorum superficialis in the forearm), a lumbrical, and most of the medial half of the sole. Thus, it is similar to the median nerve in the hand.

Answer 137

nerve of the anterior compartment of the leg. It continues onto the dorsum of the foot to innervate the two muscles that are found there, and terminates as a cutaneous nerve in the cleft between the big toe and the second toe

Answer 138

nerve of the lateral compartment of the leg. It continues in the foot as the primary source of cutaneous innervation over the dorsum of the foot. The superficial fibular nerve and deep fibular nerve are derived from the common fibular nerve near the neck of the fibula.

Answer 139

supplies the lateral part of the foot. “Sural” means calf. It follows the small saphenous vein through the calf to reach to foot. It has a complicated origin from both the tibial and common fibular nerves

Answer 140

single elastic cartilage plate covered with thin skin. It is continuous with the cartilaginous wall of the external acoustic meatus. It functions to collect sound waves and channels them down the external ear canal, concentrating high frequencies and localizing sound via phase and intensity differences.

Answer 141

extends from the auricle about 1½ inches to the tympanic membrane as an S-shaped cartilaginous and bony canal 1. Lateral 1/3—cartilaginous and lined with skin containing hair follicles, sebaceous glands, and ceruminous glands. Functions to maintain constant temperature and humidity as well as to prevent airborne particles from injuring the tympanic membrane. Medial 2/3—bony and lined with thin skin continuous with the covering of the tympanic membrane. This is the narrowest component of the external ear canal. It functions as a sound resonator for speech frequencies. Clinical Condition—acute otitis externa (swimmer's ear)

Answer 142

A. B. A thin, translucent, oval membrane, which closes the medial end of the external acoustic meatus. It moves in response to air vibrations that pass through the external acoustic meatus. These vibrations are passed to the inner ear via the ossicles. The handle and lateral process of the malleus are attached to the medial surface. Traumatic perforation of the tympanic membrane may occur as a result of foreign bodies, excessive pressure, or infection. Surgical incisions of the membrane are usually made in the posteroinferior portion to avoid the chorda tympani nerve, auditory ossicles, and numerous blood vessels present in the superior portion.

Answer 143

located in the petrous portion of the temporal bone. It contains air, nerves, the ossicles, and two muscles. The walls of the tympanic cavity form important relationships with other structures of the skull. The auditory tube connects the middle ear anteriorly with the nasopharynx.

Answer 144

Roof—a thin sheet of bone, which separates the tympanic cavity from the dura mater, and temporal lobe of the brain Floor—layer of bone which separates tympanic cavity from the internal jugular vein 3. Lateral wall—tympanic membrane Medial wall—formed by the basal coil of the cochlea Anterior wall—a narrow, thin plate of bone containing openings for the tensor tympani muscle, auditory tube, and the exit of the chorda tympani nerve 6. Posterior wall—contains openings to mastoid air cells and an aperture for the entrance of the chorda tympani nerve. A small projection of bone forms the pyramidal attachment for the stapedius muscle.

Answer 145

The resting air pressure on both sides of the tympanic membrane must be equal for the membrane to be free to move as sound waves strike it. The outside of the eardrum is exposed to atmospheric pressure that reaches it through the ear canal. The inside of the membrane is also exposed to atmospheric pressure via the auditory tube, which connects the middle ear to the nasopharynx.

Answer 146

2. The cartilaginous portion of the tube normally remains closed except during swallowing or yawning. Opening the auditory tube involves the tensor veli palatini and the salpingopharyngeus muscles. Swelling of the mucous membrane lining the tube can easily block it, leading to resorption of air in the middle ear and subsequent interference of tympanic membrane movement, diminished hearing, and fluid build-up in the middle ear.

Answer 147

lateral process (handle) and manubrium are attached to the eardrum; the head of the malleus articulates with the body of the incus

Answer 148

articulates with the head of the malleus; short crus is attached to the posterior wall of the tympanic cavity; long crus articulates with the head of the stapes

Answer 149

base of stapes fits into the oval window on the medial wall of the tympanic cavity

Answer 150

First, the surface area of the tympanic membrane is larger that of the oval window. Second, the lever action of the ossicles provides an additional mechanical advantage. Both mechanisms function to provide an overall increase in force (with decreased amplitude) by approximately 20-fold.

Answer 151

The stapedius muscle (innervated by CN VII) inserts on the stapes and the tensor tympani muscle (innervated by CN V3) inserts on the malleus. These muscles are involved in reflex dampening of the middle ear by decreasing the range of movement of the tympanic membrane in response to loud sounds.

Answer 152

system of liquid-filled channels inside corresponding bony channels within the petrous part of the temporal bone. The channels within the bone are called the bony labyrinth and are further subdivided by a membrane-bound space called the membranous labyrinth. The membranous labyrinth contains endolymph and the end organs for hearing and balance, while the space between the bony and membranous labyrinths contains perilymph.

Answer 153

Snail shaped cochlea

Answer 154

bony chamber filled with perilymph and continuous with the scala tympani through the helicotrema at the apex of the cochlea. It opens into the vestibule of the bony labyrinth and perilymph is freely exchanged between the vestibule and the scala vestibuli. Its opening into the middle ear cavity—the oval window—is closed by the stapes

Answer 155

forms a spiral, blind tube filled with endolymph and is firmly fixed to the internal and external walls of the cochlear canal. Its roof is formed by the vestibular membrane and its floor is formed by the basilar membrane. The spiral organ is situated on the basilar membrane

Answer 156

a bony chamber filled with perilymph and continuous with the scala vestibuli. Its opening into the middle ear cavity—the round window—is closed by the secondary tympanic membrane.

Answer 157

contains hair cells that respond to vibrations induced in the endolymph by sound waves. The hair cells are found within the spiral organ and protrude into a gelatinous tectorial membrane, which lies over the spiral organ. When the basilar membrane is deflected by vibrations produced by the movement of the stapes (transmitting waves to the perilymph at the oval window), this results in bending of the hair-like projections of the sensory hair cells against the tectorial membrane. This causes the hair cells to be depolarized (or hyperpolarized). The hair cells are innervated by neurons in the spiral ganglion, which lies within the bony core of the cochlea. The central processes of the ganglion cells pass into the brain via CN VIII. If the hair cells, spiral ganglion cells, or CN VIII are damaged, the resulting deafness is called a sensorineural deafness.