Appendicular skeleton Flashcards
(19 cards)
APPENDICULAR SKELETON
the Appendicular Skeleton, which includes the bones of the upper and lower limbs.
The girdles of bones that hold and attach the upper and lower limbs to the axial skeleton
The PECTORAL GIRDLE: consists of bones that HOLD THE UPPER LIMBS IN PLACE,
The PELVIC GIRDLE: consists of bones that
HOLD THE LOWER LIMBS IN PLACE.
PECTORAL GIRDLES(PECT.TOR.AL GIR.DLES)
HOLD THE UPPER LIMBS IN PLACE,
Pectoral Girdle consists of two bones: THE CLAVICLE (collarbone) and THE SCAPULA (shoulder blade).
The pectoral girdle also provides attachment sites for many muscles that move the limb, and it promotes upper limb mobility
CLAVICLE(collarbone)
CLA.VI.CLE
an S-shaped bone
extends medially with the MANUBRIUM OF THE STERNUM and the ACROMION OF THE SCAPULA
It is the only direct connection between the pectoral girdle and the axial skeleton. Its STERNAL END (medial end) is roughly pyramidal in shape and articulates with the manubrium of the sternum, forming the sternoclavicular joint. The ACROMIAL END (lateral end) of the clavicle is broad and flattened. The acromial end articulates with the acromion of the scapula, forming the acromioclavicular joint.
The superior surface of the clavicle is relatively smooth, but the inferior surface is marked by grooves and ridges for muscle and ligament attachments. On the inferior surface, near the acromial end, is a rough tuberosity called the CONOID (kō′noyd; konoeides = cone-shaped) tubercle. The inferiorly located prominence at the sternal end of the clavicle is called the COSTAL TUBEROSITY.
Scapula (figure 8.3).
BROAD, FLAT, TRIANGULAR BONE that forms the “Shoulder Blade”
The SPINE of the scapula is a RIDGE OF BONE ON THE POSTERIOR ASPECT OF THE SCAPULA. IT is easily palpated under the skin.The spine is continuous with a larger, posterior process called THE ACROMION, which forms the bony tip of the shoulder. The acromion articulates with the acromial end of the clavicle. THE CORACOID PROCESS is the smaller, MORE ANTERIOR PROJECTION.
The Triangular Shape of the scapula FORMS THREE ANGLES, OR BORDERS
The superior border is the horizontal edge of the scapula superior to the spine of the scapula; the medial border (also called the vertebral border) is the edge of the scapula closest to the vertebrae; and the lateral border (also called the axillary border) is closest to the axilla (armpit). A conspicuous suprascapular notch (which in some individuals is a suprascapular foramen) in the superior border provides passage for the suprascapular nerve.
Between these borders are the superior, inferior, and lateral angles. The superior angle is the pointed part of the scapula between the superior and medial borders, while the inferior angle is located between the medial and lateral borders.
The lateral angle is composed primarily of the CUP-SHAPED, shallow GLENOID CAVITY, OR glenoid fossa, which ARTICULATES WITH THE HUMERUS, THE BONE OF THE ARM.
The broad, relatively smooth, anterior surface of the scapula is called the subscapular fossa
The depression superior to the spine is the supraspinous fossa;
Inferior to the spine is a broad, extensive surface called the infraspinous fossa. The supraspinatus and infraspinatus muscles, respectively, occupy these fossae.
Upper Limb
THE UPPER LIMB is composed of many LONG AND SOME SHORT BONES, which articulate to provide great movement. EACH UPPER LIMB CONTAINS 30 BONES (per arm):
1 HUMERUS, located in the brachium region(upper arm)
1 RADIUS AND 1 ULNA, located in the antebrachium region (forearm)
8 CARPAL BONES, which form the wrist
5 METACARPAL BONES, WHICH form the palm of the hand
14 PHALANGES, which form the fingers
Humerus(HU.MER.US)
The humerus is the longest and largest upper limb bone
Its proximal end has a hemispherical HEAD THAT ARTICULATES WITH THE SCAPULA.
GREATER AND LESSER TUBERCLES ARE FOR MUSCLE ATTACHMENT
The prominent greater tubercle is positioned more laterally and helps form the rounded contour of the shoulder. The lesser tubercle is smaller and located more anteromedially.
Between the two tubercles is the INTERTUBERCULAR SULCUS (or bicipital sulcus),
A DEPRESSION THAT CONTAINS THE TENDON OF THE LONG HEAD OF THE BICEPS BRACHII MUSCLE.(for biceps brachia tendons)
Distal features:
THE SHAFT of the Humerus has a ROUGHENED AREA, called the DELTOID TUBEROSITY which extends along its lateral surface for about half the length of the humerus. The deltoid muscle of the shoulder attaches to this roughened surface. THE RADIAL GROOVE (or spiral groove) is located adjacent to the deltoid tuberosity, and is where the radial nerve and some blood vessels travel.
Together, the bones of the humerus, radius, and ulna form the elbow joint
The MEDIAL AND LATERAL EPICONDYLES are bony side projections on the distal humerus THAT PROVIDE SURFACES FOR MUSCLE ATTACHMENT.
The rounded CAPITULUM is located laterally and articulates with the head of the radius.
The pulley-shaped TROCHLEA is located medially and ARTICULATES WITH THE TROCHLEAR NOTCH OF THE ULNA
the distal end of the humerus exhibits three depressions(FOSSA), two on its anterior surface and one on its posterior surface
ANTERIOR SURFACE:
RADIAL FOSSA: accommodates the head of the radius,(lateral depression for the RADIUS)
CORONOID FOSSA: accommodates the coronoid process of the ulna.(MEDIAL, for anterior ULNA)
POSTERIOR:
the posterior depression called the OLECRANON fossa accommodates the olecranon of the ULNA(LARGEST, for posterior ULNA)
FOREARM
The radius and ulna are the bones of the forearm
In anatomic position, the RADIUS is LATERAL to the ULNA
The proximal end of the radius has a distinctive disc-shaped head that articulates with the capitulum of the humerus.(JOINS WITH THE HUMERUS)
The distal ends joins with the CARRELS
RADIUA and ULNA joins with each other
At the proximal and distal ends radioulnar joints are interconnected by a ligament called the INTEROSSEOUS MEMBRANE. INTEROSSEOUS MEMBRANE (interosseous ligament), composed of dense regular connective tissue, that helps keep the radius and ulna a fixed distance apart from one another and provides a pivot of rotation for the forearm.
A narrow neck separates the radial head from the radial tuberosity (or bicipital tuberosity). The radial tuberosity is an attachment site for the biceps brachii muscle.
The ulna
the longer, medially placed bone of the forearm.
Bone responsible for forming the ELBOW JOINT with the humerus
HINGE JOINT allows the forearm to bend on the arm
plays little to no role in hand movement
proximal features:
C-shaped TROCHLEAR NOTCH interlocks with the TROCHLEA OF THE HUMERUS.
THE OLECRANON:
The olecranon articulates with the olecranon fossa of the humerus and FORMS THE POSTERIOR “BUMP” OF THE ELBOW for triceps brachia muscles
The ANTERIOR TIP OF THE TROCHLEAR NOTCH, called THE CORONOID PROCESS, articulates with the humerus at the
Lateral to the coronoid process, a smooth, curved RADIAL NOTCH ACCOMMODATES THE HEAD OF THE RADIUS and helps form the proximal radioulnar joint
Distal features:
distal end of the ulna, is a KNOBLIKE HEAD that has a posteromedial STYLOID PROCESS (“wrist bump”)
the wrist and hand
Carpals=wrist
Metacarples=palms
phalanges=fingers
CARPALS:
the carpals are small, short bones that form the “true” wrist the proximal region of the hand
The proximal row of carpal bones, listed from (LATERAL TO MEDIAL,) are the SCAPHOID, LUNATE, TRIQUETRUM, AND PISIFORM
The bones of the distal row of carpal bones are the most laterally placed. TRAPEZIUM, TRAPEZOID, CAPITATE, AND HAMATE
METACARPALS:
The BONES IN THE PALM of the hand are called METACARPALS
Five metacarpal bones articulate with the distal carpal bones and support the palm.
Roman numerals I–V (1-5) indicates the metacarpal bones, with METACARPAL I(1) LOCATED AT THE BASE OF THE THUMB, and METACARPAL V(5) AT THE BASE OF THE LITTLE FINGER.
PHALANGES:
THE BONES OF THE DIGITS ARE THE PHALANGES
There are THREE PHALANGES IN EACH OF THE SECOND THROUGH FIFTH FINGERS (proximal, middle , and distal) and TWO PHALANGES ONLY IN THE THUMB, ALSO KNOWN AS THE POLLEX(proximal and distal), for a total of 14 phalanges per hand. The proximal phalanx articulates with the head of a metacarpal, while the distal phalanx is the bone in the very tip of the finger. The middle phalanx of each finger lies between the proximal and distal phalanges; however, a middle phalanx is not present in the thumb.
pelvic girdle
the adult pelvis is composed of four bones: THE SACRUM, THE COCCYX, AND THE RIGHT AND LEFT OSSA COXAE
PELVIC GIRDLE REFERS TO THE LEFT AND RIGHT OSSA COXAE ONLY.
SACRUM & COCCYX= the PELVIS
OS COXAE:
The os coxae is commonly referred to as the “hip bone” (and sometimes as the coxal bone or the innominate bone).
Each os coxae(HIP BONE) is formed from three separate bones: THE ILIUM, THE ISCHIUM, AND THE PUBIS. These three bones fuse between the ages of 13 and 15 years to form the single OS COXAE.
ARTICULATIONS:
Each os coxae articulates POSTERIORLY WITH an auricular surface of the SACRUM at the sacroiliac joint.
The femur articulates with a deep, curved depression on the LATERAL surface of the os coxae called the ACETABULUM
Anteriorly with other OS COXAE
The three bones that form the os coxae (ilium, ischium, and pubis) all contribute a portion to the acetabulum.
Thus, the acetabulum represents a region where these bones have fused.
ilium
The LARGEST OF THE THREE COXAL BONES IS THE ILIUM
which forms the superior region of the os coxae and the largest portion of the acetabulum surface.
The wide, fan-shaped portion of the ilium is called THE ALA
The ala terminates INFERIORLY AT A RIDGE CALLED THE ARCUATE LINE
On the MEDIAL SIDE of the ala is A DEPRESSION TERMED the ILIAC FOSSA.
From a lateral view, an observer sees ANTERIOR, POSTERIOR, AND INFERIOR GLUTEAL LINES THAT are ATTACHMENT SITES FOR THE GLUTEAL MUSCLES OF THE BUTTOCK
The SUPERIORMOST RIDGE of the ilium IS THE ILIAC CREST.
The iliac crest arises anteriorly from a projection called the ANTERIOR SUPERIOR ILIAC SPINE AND EXTENDS POSTERIORLY TO THE POSTERIOR SUPERIOR ILIAC SPINE.
The posterior inferior iliac spine is adjacent to a prominent GREATER SCIATIC NOTCH, through which the sciatic nerve travels to the lower limb.
AURICULAR SURFACE, where the ilium articulates with the sacrum at the sacroiliac joint.
The ilium fuses with the ISCHIUM near the superior and posterior margins of the acetabulum.
Posterior to the acetabulum, the prominent MEDIAL PROCESS ; ISCHIAL SPINE PROJECTS medially.
The bulky bone superior to the ischial spine is called the ischial body.
the lesser sciatic notch is a semicircular depression inferior to the ischial spine.
The posterolateral border of the ischium is a roughened projection called the ISCHIAL TUBEROSITY(SUPPORTS WEIGHT OF THE BODY
An elongated ISCHIAL RAMUS of the ischium extends from the ischial tuberosity toward its anterior fusion with the pubis.
THE PUBIS:
The pubis fuses with the ilium and ischium at the acetabulum. The ischial ramus fuses anteriorly with the inferior pubic ramus to form the ischiopubic ramus (see figure 8.7). The superior pubic ramus originates at the anterior margin of the acetabulum. The obturator (ob′too-rā-tŏr; obturo = to occlude) foramen is a space in the os coxae that is encircled by both pubic and ischial rami. A roughened ridge called the pubic crest is located on the anterosuperior surface of the superior ramus, and it ends at the pubic tubercle. The pubic tubercle is an attachment site for the inguinal ligament. A roughened area on the anteromedial surface of the pubis, called the symphysial (sim′fizē-ăl; growing together) surface, denotes the site of articulation between the pubic bones. On the medial surface of the pubis, the pectineal (pek-tin′ē-ăl; ridged or relating to the pubis) line originates and extends diagonally across the pubis to merge with the arcuate line.
Lower Limb
The arrangement and numbers of bones in the lower limb are similar to those of the upper limb. However, since the bones of the lower limb are adapted for weight bearing and locomotion, they may be shaped somewhat differently and articulate differently than the comparable bones of the upper limb. EACH LOWER LIMB CONTAINS 30 BONES:
1 FEMUR, LOCATED in the femoral region(thigh)
1 PATELLA (KNEECAP), located in the patellar region
1 TIBIA AND 1 FIBULA, located in the crural region(leg)
7 TARSAL BONES, which form the bones of the ankle and proximal foot
5 METATARSAL BONES, which form the arched part of the foot(sole of foot)
14 PHALANGES, WHICH form the toes
THE FEMUR
The femur is the longest bone in the body as well as the strongest and heaviest. The nearly spherical head of the femur articulates with the pelvis at the acetabulum. A tiny ligament connects the acetabulum to a depression in the head of the femur, called the fovea, or fovea capitis. Distal to the head, an elongated, constricted neck joins the shaft of the femur at an angle. This results in a medial angling of the femur, which brings the knees closer to the midline.
Two massive, rough processes originate near the proximal end of the femur and serve as insertion sites for the powerful hip muscles.
-GREATER TROCHANTER and LESSER TROCHANTER
Anteriorly, a raised INTERTROCHANTERIC LINE extends between the two trochanters and marks the distal edge of the hip joint capsule.
GLUTEAL TUBEROSITY marks the attachment of the gluteus maximus muscle.
The prominent feature on the posterior surface of the shaft is an elevated, midline ridge called the LINEA ASPERA. THIS RIDGE DENOTES THE ATTACHMENT SITE FOR MANY THIGH MUSCLES.
Distally, the linea aspera branches into MEDIAL AND LATERAL
On the distal, inferior surface of the femur are two smooth, oval articulating surfaces called the MEDIAL AND LATERAL CONDYLES
Superior to each condyle are projections called the medial and lateral epicondyle, respectively. When you flex your knee, you can palpate these epicondyles in the thigh on the sides of your knee joint. The medial and lateral supracondylar lines terminate at these epicondyles. On the distal posterior surface of the femur, a deep intercondylar fossa separates the two condyles. Both condyles continue from the posterior surface to the anterior surface, where their articular faces merge, producing an articular surface with elevated lateral borders. This smooth anteromedial depression, called the patellar surface, is the place where the patella articulates with the femur.
THE PATELLA
THE PATELLA or kneecap, is a large, roughly triangular sesamoid bone located within the tendon of the quadriceps femoris muscle.
The patella allows the tendon of the quadriceps femoris to glide more smoothly, and it protects the knee joint. The superior base of the patella is broad, and its inferior apex is pointed. The patella may be easily palpated along the anterior surface of the knee. The posterior aspect of the patella has an articular surface that articulates (connects) with the patellar surface of the femur.
Tibia and Fibula
Anatomists identify the part of the lower limb between the knee and the ankle as the crural region, or leg. The skeleton of the leg has two parallel bones, the thick, strong tibia and a slender fibula.These two bones are connected by an interosseous membrane composed of dense regular connective tissue, which extends between their interosseous borders. The interosseous membrane stabilizes the relative positions of the tibia and fibula, and additionally provides a pivot of minimal rotation for these two bones.
2 BONES OF THE LEG
PARALLEL TO EACH OTHER
TIBIA IS MEDIAL TO FIBULA
TABIA:
The tibia is medial and the only weight-bearing bone of the crural region.
Its broad, superior head has two relatively flat surfaces, the MEDIAL AND LATERAL CONDYLES, which articulate with the medial and lateral condyles of the femur, respectively.
Separating the the tibia is a prominent ridge called the intercondylar eminence. On the proximal posterolateral side of the tibia is a FIBULAR ARTICULAR FACET where the head of the fibula articulates to form the superior (or proximal) tibiofibular joint.
The rough anterior surface of the tibia near the medial and lateral condyles is the tibial tuberosity, which can be palpated just inferior to the patella and marks the attachment site for the patellar ligament.
THE ANTERIOR TIBIAL BORDER (or margin) is a ridge that extends distally along the anterior tibial surface from the tibial tuberosity. This crest can be readily felt through the skin and is commonly referred to as the “shin.”
The tibia narrows distally, but at its medial border, it forms a large, prominent process called the MEDIAL MALLEOLUS
On the inferior distal surface of the tibia is the smooth inferior ARTICULAR SURFACE FOR the talus, one of the tarsal bones.
The fibula is the long, thin, lateral bone of the leg. It has expanded proximal and distal ends. Although the fibula does not bear any weight, it is the origin for several muscles. Along the lateral edge of the tibia, the fibula articulates with the surface of the tibia. The rounded, knoblike head of the fibula is slightly inferior and posterior to the lateral condyle of the tibia. On the head, the smooth articular facet articulates with the tibia. Distal to the fibular head is the neck of the fibula, followed by its shaft. Although the fibula does not bear or transfer weight, its distal tip, called the lateral malleolus, extends laterally to the ankle joint, where it provides lateral stability. Palpate the lateral side of your ankle; the bump you feel is your lateral malleolus.
FIBULA
The fibula is the long, thin, lateral bone of the leg. It has expanded proximal and distal ends. Although the fibula does not bear any weight, it is the origin for several muscles. Along the lateral edge of the tibia, the fibula articulates with the surface of the tibia. The rounded, knoblike head of the fibula is slightly inferior and posterior to the lateral condyle of the tibia. On the head, the smooth articular facet articulates with the tibia. Distal to the fibular head is the neck of the fibula, followed by its shaft. Although the fibula does not bear or transfer weight, its distal tip, called the lateral malleolus, extends laterally to the ankle joint, where it provides lateral stability. Palpate the lateral side of your ankle; the bump you feel is your lateral malleolus.
THE ANKLE AND FOOT
The bones that form the ankle and foot are the tarsals, metatarsals, and phalanges
- Supports body weight
- Acts as a lever to propel body forward when walking
- segmentation makes foot pliable and adapted to uneven ground
TARSUS:
The seven tarsals of the ankle and proximal foot are analogous to the eight carpal bones of the wrist, although their shapes and arrangement are different. The tarsal bones are thoroughly integrated into the structure of the foot because they help the ankle bear the body’s weight
The largest tarsal bone is the CALCANEUS which FORMS THE HEEL. Its posterior end is a rough, knob-shaped projection that is the point of attachment for the calcaneal (Achilles) tendon extending from the strong muscles on the posterior side of the leg.
The superiormost and second-largest tarsal bone is the TALUS.The superior aspect of the talus articulates with the articular surface of the TIBIA.
The NAVICULAR bone is on the medial side of the ankle. The talus, calcaneus, and navicular are considered the proximal row of tarsal bones.
The distal row is formed by a group of four tarsal bones. The THREE CUNEIFORM BONES are wedge-shaped bones with articulations between them, positioned anterior to the navicular bone. They are named according to their position: MEDIAL CUNEIFORM, INTERMEDIATE CUNEIFORM, AND LATERAL CUNEIFORM BONES.
The laterally placed CUBOID BONE articulates at its medial surface with the lateral cuneiform and the calcaneus. The distal surfaces of the cuboid bone and the cuneiform bones articulate with the metatarsal bones of the foot.
THE METATARSAL
The METATARSAL BONES of the foot are five long bones similar in arrangement and name to the metacarpal bones of the hand.
They form the sole of the foot and are identified with Roman numerals I–V,
Arches of the Foot
Normally, the sole of the foot does not rest flat on the ground. Rather, the foot is arched, which helps it support the weight of the body and ensures that the blood vessels and nerves on the sole of the foot are not pinched when we are standing. The three arches of the foot are the medial longitudinal, lateral longitudinal, and transverse arches
THE MEDIAL LONGITUDINAL arch extends from the heel to the great toe(hallux). Highest Arch
The medial longitudinal arch prevents the medial side of the foot from touching the ground and gives our footprint its characteristic shape
THE LATERAL LONGITUDINAL arch is not as high as the medial longitudinal arch, so the lateral part of the foot does contribute to a footprint. This arch extends between the little toe and the heel,(the LOWEST arch)
The TRANSVERSE ARCH RUNS perpendicular to the other arches. It is formed from the distal row of tarsals and the bases of all five metatarsals
