Quiz 2 Flashcards
What is the neck and what are its functions?
fibromuscular tube that connects the head with the thorax. Its functions include being a passageway for a portion of the respiratory system (the larynx and trachea start in the neck and end in the lungs), is a passageway for portions of the digestive system (the esophagus connects the pharynx to the stomach), is a passage of the brachial plexus from the neck into the upper limb, it is the location of the thyroid and parathyroid endocrine glands, and includes muscle activities such as 1) movement of the head on the neck, 2) stabilizing the head on the neck, 3) movements of the neck, 4) inspiration, 5) deglutition
What are the bones in the neck?
1) cervical vertebrae, which protect the spinal cord and vertebral artery, serve as attachments for muscles, and assist with movement. 2) the hyoid bone, which is an attachment for muscles (especially those of the tongue and pharynx)
What are the regions of the neck?
1) Posterior Neck (contains postural muscles that are innervated by the dorsal rami). 2) Anterior and lateral neck (which divide the region into the posterior and anterior triangles)
What are the boundaries of the posterior triangle?
The posterior border of the sternocleidomastoid, the anterior border of the trapezius, and the middle portion of the clavicle
What are the primary contents of the posterior triangle?
1) spinal/accessory portion of cranial nerve XI, 2) cutaneous branches of cervical plexus of nerves, 3) phrenic nerve
What are the boundaries of the anterior triangle?
the anterior border of the sternocleidomastoid, and the mandible.
What are the primary contents of the anterior triangle?
the hyoid bone (level of C3), thyroid cartilage (part of both larynx and pharynx– C4-C5), cricoid cartilage (primary cartilage of the larynx– C6), superior portion of the trachea, and thyroid glands (C5 to T1 and covered by infrahyoid muscles), submandibular salivary gland
How can the thyroid cartilage be easily identified?
It has a prominent projection, the laryngeal prominence (Adam’s apple)
What is the vertebral level of the hyoid bone?
C3
What is the vertebral level of the thyroid cartilage?
C4-C5
What is the vertebral level of the cricoid cartilage?
C6
What is the vertebral level of the thyroid gland?
C5-T1
What is the carotid sheath?
A fascial sheath that is found deep to the sternocleidomastoid muscle. It contains the internal jugular vein, common and internal carotid arteries, deep cervical lymph nodes, carotid sinus nerve, sympathetic nerve fibers, and the vagus nerve. Communicates with the mediastinum of the thorax and the cranial cavity, which are pathways for the spread of infection.
What is the viscera contained in the neck?
larynx, trachea, esophagus, thyroid and parathyroid glands
What determines the direction in which an infection in the neck may spread?
Fascial planes
What is the platysma?
A broad, thin sheet of muscle. Muscle of facial expression that arises in subcutaneous tissue covering the superior parts of the deltoid and pectoralis major muscle and sweeps superomedially over the clavicle to the inferior border of the mandible.
What does deep cervical fascia consists of and what do they allow for?
Three fascial layers: investing pretracheal, and prevertebral, which support the viscera, muscles, vessels, and deep lymph nodes. The fascial layers privode the slipperiness that allows structures in the neck to move and pass over one another without difficulty, such as when you swallow.
What is the advantage of natural cleavage planes and what forms them?
They are formed by the layers of the deep cervical fascia. The natural cleavage planes allows for separation of tissues during surgery.
Describe the investing layer of deep cervical fascia.
Most superficial layer. Surrounds the entire neck. Deep to subcutaneous tissue. At the four corners of the neck, the investing layer splits into superficial and deep layers of deep fascia to encole the right and left SCM and trapezius. Superiorly, it attaches to the superior nuchal line of the occipital bone, mastoid processes, zygomatic arches, inferior border of the mandible, hyoid, and spinous processes. Just inferior to the mandibular attachment, it splits to enclose the submandibular gland. Posterior to the mandible, it splits to form the fibrous capsule of the parotid gland. Inferiorly, it attaches to the manubrium, clavicles, acromions, and scapular spines. It covers the C7 spinous process and the nuchal ligament. It is divided into two layers that enclose the SCM. A suprasternal space lies between these layers and encloses tthe inferior ends of the anterior jugular veins and lymph nodes.
Describe the pretracheal layer of deep cervical fascia
The pretracheal layer of deep cervical fascia is limited to the anterior part of the neck. It extends inferiorly from hyoid to the thorax, where it blends with the fibrous pericardium covering the heart. It includes the thin muscular part (encloses the infrahyoid muscles) and a visceral part, which encloses the thyroid gland, trachea, and esophagus. Continuous with the buccopharyngeal fascia and blends with carotid sheaths.
Describe the prevertebral layer of deep cervical fascia.
Forms tubular sheath for the vertebral column and the muscles associated with it, Fuses with the anterior longitudinal ligamnt at T3. Extends as the axillary sheath, which surrounds the axillary vessels and the brachial plexus.
Describe the retropharyngeal space.
permits movement of the pharynx, esophagus, larynx, and trachea relative to the vertebral column during swallowing. Largest and most clinically important space in the neck because it is the major pathway for the spread of infection.
What helps prevent the spread of abscesses?
the investing layer of deep cervical fascia.
What separates the sternal and clavicular heads of the sternocleiodomastoid?
the lesser supraclavicular fossa
What is torticollis?
a contraction of the cervical muscles that produces a twisting of the neck and slanting of the head. Can be congenital (results from a fibrous issue tumor that develops in the SCM, or the SCM is injured when an infant’s head is pulled excessively during a difficult birth. This tearing results hematoma that may develop into a fibrous mass entrapping a branch of CN XI, which would denervate part of the SCM). Spasmodic torticollis, which begins in adulthood, involves bilaterial combination of lateral neck muscles (especially SCM).
What are the superficial muscles of the neck?
The platysma, the trapezius, and the sternocleidomastoid
What are the infrahyoid muscles?
4 thin muscles found on either side of hte midline of hte neck, inferior to the hyoid bone. All attach to the hyoid and help depress the hyoid after swallowing. Also steady the hyoid bone so that the muscles of the tongue and pharynx can use the hyoid bone as a strut when they contract. They are innervated by C1-C3 (ansa cervicalis) and include the sternohyoid, omohyoid, sternothyroid, and thyrohyoid.
What are the suprahyoid muscles?
The suprahyoid muscles lie superior to the hyoid bone. Involved with the process of swallowing, depressing the mandible when opening the mouth wide, and protrusion of the tongue.
What innervates the sternocleidomastoid?
Cranial Nerve XI
Why is the SCM an important landmark?
It can be used to find the carotid artery pulse and locating the brachial plexus when attempting to perform brachial plexus nerve block.
Where are the suprahyoid muscles located and what do they do?
Suprahyoid muscles lie superior to hyoid bone. They are involved with the process of swallowing, depressing the mandible when opening the mouth wide, and protrusion of the tongue.
Which movements of the neck do not involve the 7 cervical vertebrae?
none.
What are the five groups of muscles of the anterior neck?
Superficial, Infrahyoid, Suprahyoid, Lateral vertebral
Prevertebral
What are the muscles of the suprahyoid?
mylohyoid, digastric, geniohyoid, and stylohyoid.
What are the two muscles of contralateral rotation in the neck area that we have learned about so far?
semispinalis capitis and sternocleidomastoid
What are the muscles of the lateral vertebral group? what is their action, origin and insertion, and innervation?
Middle, Anterior, and Posterior Scalene. All of which originate from the anterior tubercles of the 3rd through the 7th cervical vertebrae and are innervated by motor branches from cervical nerves C3-C8. Acting bilaterally, they flex the neck. When the neck is steadied, they elevate the 1st and 2nd ribs during forced inspiration. Unilaterally, they flex the neck to the ipsilateral side. The anterior and middle scalene are attached to the 1st rib, while the posterior scalene inserts at the 2nd rib,
What is the scalene triangle?
A triangle between the anterior and middle scalene muscles. The base is the first rib. The triangle contains the roots and trunks of the brachial plexus and subclavian artery.
What is Thoracic Outlet Syndrome?
Poor circulation of the hand and parathesia (tingling) along the medial portion of the hand. This is caused when the artery and lower portion of the brachial plexus get compressed within the scalene triangle by tight muscles, the presence of a cervical rib, a tumor, or inflammation.
What are the prevertebral muscles?
longus coli (superior oblique, inferior oblique, and vertical portion), longus capitis, rectus capitis anterior, and rectus capitis lateralis
What is the primary action of the rectus capitis lateralis?
to stabilize the skull on C1
Where is the best place to feel the pulse of the subclavian artery?
The greater supraclavicular fossa, within the posterior triangle of the neck just superior to the clavicle.
Where is the best place to feel the pulse of the common carotid artery?
Push aside the sternocleidomastoid and press lightly against transverse processes of cervical vertebrae
What does the external carotid artery supply? The internal?
External supplies the face and scalp, internal supplies the brain.
What is the aorta?
The aorta is the largest artery in the body. It arises from the left ventricle of the heart and is divided into 3 segments: 1) ascending– upward from the right ventricle. The right and left coronary arteries are branches to this portion of the aorta. The arch of the aorta is a continuation of the ascending aorta. It commences at T4, arches in the thorax to return to T4 posteriorly.
What branches off of the aortic arch?
the brachiocephalic trunk (arising from the right side of the arch and ascending into the neck). The trunk divides into the right common carotid and right subclavian, and the left common carotid and left subclavian.
At what level do the common carotid arteries divide?
C4 (upper border of the thyroid cartilage)
What does the subclavian artery supply?
the lower neck and upper limb
What does the vertebral artery supply?
the cervical spinal cord and brain
What are the boundaries for the vertebral artery?
anterior scalene laterally, longus coli medially, subclavian artery at its base, and the transverse process of C6 (carotid tubercle) at the apex.
What forms the brachiocephalic veins?
the union of the internal jugular and subclavian veins. The origin of these veins lies directly posterior to the sternoclavicular joints. The left vein crosses directly posterior to the manubrium to join the right brachiocephalic vein to form the superior vena cava.
which of the infrahyoid muscles are part of the superficial plane? the deep plane?
superficial plane = sternohyoid and omohyoid; deep plane = sternothyroid and thyrohyoid
Which muscle limits superior expansion of an enlarged thyroid gland?
sternothyroid
which muscle looks like a continuation of the sternothyroid?
thyrohyoid
What is the major venous channel draining the upper limb?
the subclavian vein
What does the occipital artery branch off of and what does it supply?
branches off of the external carotid artery and supplies the posterior half of the scalp
What does the subclavian artery do?
supply blood to upper limb
Where does the posterior auricular artery branch off and what does it do?
It branches off of the external carotid artery and contributes to the blood supply of adjacent muscles, parotid gland, facial nerve, and structures in the temporal bone, auricle, and scalp.
What does the superior thyroid artery do and where does it branch off?
Most inferior of the three anterior branches of the external carotid, runs to the thyroid gland. Supplies thyroid gland and gives off branches to the infrahyoid and SCM , and gives rise to the ascending laryngeal (which supplies larynx)
Where does the lingual artery branch off and what does it do?
arises from external carotid. gives dorsal lingual arteries to the posterior tongue and then bifurcates into the deep lingual and sublingual.
What does the internal jugular vein do?
drains blood from the brain, anterior face, cervical viscera, and deep muscles of the neck. The IJV leaves the cervical region by passing deep to the SCM
What comprises the brachiocephalic vein?
The IJV and the subclavian
What is the significance of the inferior bulb of the IJV?
the bulb has a bicuspid valve that permits blood to flow toward the heart while preventing backflow into the vein
The right subclavian artery arises from the ____, while the left subclavian artery arises from the______
the right subclavian artery arises from the brachiocephalic trunk, while the left subclavian artery arises from the arch of the aorta
When does the subclavian artery turn into the axillary artery?
the first rib
What are the branches of the subclavian artery?
vertebral artery, internal thoracic artery, and thyrocervical trunk from the first part of the subclavian; the costocervical trunk from the second part of the subclavian, and the dorsal scapular artery from the third part of the subclavian.
What does the thyrocervical trunk do?
2 lateral branches– the suprascapular artery, which supplies the muscles on the posterior scapula, and the cervicodosal trunk.
What does the thyroid gland do?
thyroid gland produces thyroid hormone, which controls the rate of metabolism and calcitonin, which controls calcium metabolism. it is located at C5-T1 vertebrae. blood supply is provided by inferior and superior thyroid arteries.
Where are the nerves of the thyroid gland derived from?
the cervical sympathetic ganglia
What is the larynx?
complex organ of voice production that lies in the anterior part of the neck at the level of C3-C6. If connects the inferior part of the pharynx to the trachea. Its most vital function is to protect the airway passage, especially during swallowing, when it serves as a sphincter of the lower respiratory tract.
Where do the inferior horns of the thyroid cartilages articulate with the lateral surfaces of the cricoid cartilages?
the cricothyroid joints. the main movement at these synovial joints are rotation and gliding of the thyroid cartilage, which results in changes of the length and tension of the vocal folds.
which is stronger, the thyroid or cricoid cartilage?
cricoid
which is larger, the thyroid or cricoid cartilage?
thyroid
what are the vocal folds?
source of sounds (tone) that come from the larynx. the vocal folds produce audible vibrations when their free margins are closes apposed during phonation and air is forcibly expired intermittently. they also serve as main inspiratory sphincter of the larynx when they are tightly closed. complete adduction of folds forms sphincter that prevents air entry.
What are the two groups of larynx muscles?
1) extrinsic– move the larynx as a whole. the infrahyoid muscles are depressors of hte hyoid and larynx, while the suprahyoid and stylopharyngeus muscles are elevators of the hyoid and larynx.
2) intrinsic– move hte laryngeal parts– altering length and tension in laryngeal folds.
What are the three segments of the pharynx and their functions?
1) nasopharynx (posterior extension of the nasal cavities down to the soft palate)– respiratory function.
2) oropharynx (posterior to the mouth– from soft palate to base of tongue/ epiglottis)– digestive function. swallowing.
3) laryngopharynx– post. to pharynx– from superior border of epiglottis to inferior border of cricoid cartilage. communicates with larynx
What are the three nerve groupings of the cervical nerves?
1) the cervical plexus of nerves, comprise a somatic nerve plexus made up of ventral rami of C1-4 (C1 has no DRG). The branches of this plexus supply the skin and musculature of anterior neck. Have sensory, motor, and mixed branches.
2) brachial plexus of nerves
3) the cervical sympathetic nerves, which have three components: a) superior, middle, and inferior cervical ganglia, b) postganglionic axons that synapse in these ganglia have their cell bodies in the intermediolateral column of grey matter in thoracic spinal cord
c) postganglionic sympathetic neurons– cell bodies in paravertebral ganglia (innervate heart, skin of neck and upper limb, skin and vasculature of face and scalp, and structures in the eye).
What are the sensory nerves of the cervical plexus?
- Lesser Occipital (C2)
- Great Auricular (C2/3)
- Transverse Cervical (C2/3)
- Supraclavicular (C3/4)
What are the motor nerves of the cervical plexus?
- Ansa Cervicalis (C1-3), which sends motor info to the infrahyoid muscles
- Branches to scalene and prevertebral
What are the mixed nerves of the cervical plexus?
- phrenic (C3-5), which sends motor to diaphragm, sensory from diaphragmatic and mediastinal pleura, and sensory from pericardium
What innervates the posterior aspect of the scalp and neck?
dorsal rami of cervical nerves
what innervates the anterior neck?
branches from C2-C4
What dermatome is associated with C1?
None- C1 has no DRG and thus no sensations associated with it. C1 only has somatic motor axons.
What is referred somatic pain? give an example.
pain in one somatic area felt in another somatic area. For example, the supraclavicular nerves convey sensation from the skin covering the clavicle and top of shoulder. These regions comprise the C3 & 4 dermatomes. The phrenic nerve conveys sensation from portions of the pericardium and the pleura. This nerve contains sensory axons that are also derived from the C3 and C4 ventral rami. Pleurisy (pain from irritated pleura) and Pericarditis (pericardium pain) can be felt on the shoulder.
How does the autonomic nervous system differ from the somatic nervous system?
the autonomic nervous system affects the viscera (internal organs), vessels, and smooth muscles
What are the two subsystems of the autonomic nervous system?
1) the sympathetic (which exerts its effect on the heart, smooth muscle, and glands by secretion of norepinepherine (Andrenergic) and 2) parasympathetic, which exerts its effect on the heart, smooth muscle, and glands by secretion of acetylcholine (cholinergic)
describe the sympathetic nervous system
it originates in the interomediolateral horn of the spinal cord from T1-L2 and forms a sympathetic chain along either side of the vertebral column. Connected by rami communicans (white = pre-ganglionic, while grey = post-ganglionic)
Describe the preganglionic pathway
preganglionic sympathetic axon travels from the interomediolateral horn of the spinal cord via ventral ramus to a white ramus, and then conducted to a paravertebral ganglion. Once in the sympathetic chain, there are three possible actions:
1) Synapse with the cell body of a postganglionic neuron in the paravertebral ganglion they enter
2) Ascend or descend in the sympathetic chain to synapse in a paravertebral ganglion either superior to or inferior to the one they entered.
3) Pass through the paravertebral ganglia without synapsing to later synapse with a paravertbral ganglia in the abdomen/gut (these long preganglionic axons form a component of a splanchnic nerve– visceral path).
What are the two types of visceral motor neurons?
1) preganglionic – cell bodies within grey matter of the thoracic and upper lumbar regions of the spinal cord (T1-L2). These neurons carry info from the spinal cord to the paravertebral ganglia.
2) the postganglionic neurons have their cell bodies in paravertebral ganglia. their axons bring sympathetic information to the effector organ (e.g. cardiac muscle, smooth muscle, glands).
What forms the sympathetic chain, where is it located, and why is it important?
located alongside the vertebral bodies, the sympathetic chain is formed by the paravertebral ganglia, which contain the cell bodies of postganglionic sympathetic neurons. This is the site of synapse between preganglionic and postganglionic neurons.
What is the rami communicans?
2 roots that connect paravertebral ganglia to ventral rami. The white ramus contains preganglionic sympathetic axons, connecting the paravertebral ganglia in the thoracic and upper lumbar regions to ventral rami T1-L2. The grey ramus contains the axons of postganglionic sympathetic neurons and connects all paravertebral ganglia in the neck, thorax, abdomen, and pelvis to the ventral rami.
What are the pathways of the postganglionic sympathetic axons?
1) they can enter a grey ramus and be conveyed to and distributed with a ventral ramus. Cutaneous pathway (distributed to sweat glands, erector pili muscles), and cutaneous blood vessels. This pathway is involved with temperature regulation.
2) do not enter grey rami but instead are directly distributed to the heart and lungs to form the sympathetic components of the cardiac and pulmonary plexi
3) do not entry grey rami but instead are directly distributed with the carotid arteries to cutaneous structures (sweat glands and blood vessels) in the skin of the face and the scalp and to the dilator pupilae muscle of the eye. Form the carotid plexus
Where are the cell bodies of postganglionic sympathetic neurons located?
within the paravertebral ganglia
What are the three sympathetic ganglia in the cervical region?
1) superior, 2) middle, 3) inferior (often fuses with the first thoracic ganglion to form a large Stellate ganglion– star shaped)
How are the postganglionic sympathetic axons distributed in the cervical sympathetic region?
1) inferior and middle cervical ganglion can either pass through the grey ramus to be distributed in the upper limb via the brachial plexus, or 2) do not enter a grey ramus but go directly to participate in cardiac and pulmonary plexi
2) Superior cervical ganglions pass through the grey ramus to be distributed to the skin of the neck via the cervical plexus, or are distributed with branches of the carotid artieres to the skin of the face and scalp and the dilator pupilae muscle of the eye, or go directly oto join the cardiac and pulmonary plexi
What is Horner’s Syndrome?
Syndrome that indicates a lesion of the superior cervical
sympathetic ganglion.
Symptoms include: 1) ptosis (drooping eyelid) due to loss of sympathetic input to the superior tarsal muscle, smooth muscle in the upper eyelid, 2) myosis– constricted pupil, due to the inabiity to dilate the pupil. The dilator pupilate muscle is a smooth muscle that needs sympathetic input to function. 3) Anhydrosis– loss of sweating– of the affected side of the face because the sweat glands of the face require sympathetic input, 4) redness of the affected side of the face resulting from a loss of vasoconstrictive sympathetic fibers
Causes include:
Dilation/Aneurysm of carotid
vessels, Nerve blocks, Pressure on the sympathetic
trunk from lung tumors or trauma can decrease preganglionic input into the superior cervical ganglion.
Where do the roots of brachial plexus appear?
between anterior and middle scalene
What does the suprascapular nerve supply?
the supraspinatus and infraspinatus
what makes up the cervical plexus?
anterior rami of C1-C4
What is the lower occipital nerve number?
C2
What is the great auricular nerve number?
C2 and C3
What is the transverse cervical nerve number?
C2 and C3
What does the great auricular nerve supply?
the skin and sheath over the parotid gland, posterior aspect of the auricle, and the area of the skin overlying the angle of the mandible to the mastoid process
what does the transverse cervical nerve supply?
the skin covering the anterior cervical region
What are the branches of the external carotid arteries?
Seven Angry Ladies Fight Over PMS (from inferior to superior). Superior thyroid, ascending pharyngeal, lingual, facial, occipital, posterior auricular, maxillary, superficial temporal
what numbers are the supraclavicular nerves and what do they supply?
C3 and C4, supply the skin over the shoulder
What supplies the sole motor supply to the diaphragm?
phrenic nerve (C3 C4 C5)
Where does the phrenic nerve lie?
anterior to the scalene
What are the three pairs of major nerves in the root of the neck?
vagus nerves, phrenic nerves, and sympathetic trunks
Which ganglion usually fuse together to form a stellate ganglion?
the inferior cervical ganglion with the first thoracic ganglion
When does the axillary artery become the brachial artery?
after the pectoralis major
What is winged scapula?
when the serratus anterior doesn’t hold down the scapula, so it pops out when the arms are forward.
what is the only connection between the axial skeleton and the shoulder girdle?
the sternoclavicular joint
What is contained in the axillary sheath? What other important things are found in the axilla?
axillary artery, axillary vein, and roots and trunks of brachial plexus. The axilla also contains the axillary lymph nodes, which receive lymph from the upper limb and most of the breast. They are important regarding the spread of breast cancer from the breast to other parts of he body.
where does the axillary artery begin and end?
begins at the lateral border of the 1st rib and ends at the inferior border of the teres major
What are the 6 branches of the axillary artery and where do they supply?
1) superior thoracic – 1st 2 intercostal spaces
2) thoracoacromial trunk– shoulder girdle and attached muscles
3) lateral thoracic– lateral chest wall, including serratus anterior
4) posterior humeral circumflex–
5) anterior humeral circumflex–
6) subscapular, which has 2 branches: a) circumflex scapular– dorsal surface of scapula where it participates in scapular anastmosis with transverse cervical and suprascapular branches of thyrocervical trunk, b) thoracodorsal supplies latissimus dorsi
which branch of the axillary artery accompanies the the axillary nerve through the quadrangular space?
posterior humeral circumflex
what does anastmosis mean?
The connection of separate parts of a branching system to form a network.
Which branch of the axillary artery forms an anastmosis with the anterior humeral circumflex?
the posterior humeral circumflex
Which of the axillary branches is characterized as small?
anterior humeral circumflex
which axillary artery branch supplies the latissimus dorsi?
the thoracodorsal branch of the subscapular
What is the significance of the scapula anastmosis?
important route for collateral circulation around scapula. Begins at 1st part of subclavian artery into connection with axillary artery. Blood could still get to the arm, forearm, and hand even if the terminal portion of the axillary artery were occluded.
What junction forms the axillary vein?
brachial and basilic
when does the cephalic vein join the axillary vein?
near the termination of the axillary vein by the first rib
characterize movements at the SC (sternoclavicular joint)
largely passive in that they occur as a result of mascles acting directly on the scapula resulting in active movement by the scapula.
What is the significance of the acromiclavicular joint?
occurs between the clavicle and the acromion of the scapula. clavicle can act as a strut maintaining the upper limb away from the thorax permitting greater range of upper limb motion. Joint also provides static stability to the upper limb reducing the need to use muscle energy to keep upper limb in proper alignment
what is the most moveable joint in the body? why is this ROM necessary?
glenohumeral joint between head of humerus and glenoid cavity of scapula. this mobility is necessary to maximize manipulation abiity of the hand
what is the scapulothoracic joint?
not a true joint, where the scapula is suspended on the thoracic wall.
What is the relationship between the clavicle and scapula in terms of movement?
inverse (when one goes up the other goes down, when one protracts the other retracts, and visa versa)
When does active versus passive movement occur with regards to the scapulothoracic articulation?
active movement occurs when muscles act directly to move the scapula on the thorax. Passive movement occurs when the muscles act directly on the arm resulting in movements at the shoulder joint.
What are the extrinsic muscles of the shoulder girdle?
levator scapula, trapezius, latissimus dorsi, pectoralis minor, serratus anterior, rhomboid major and minor
What is the pectoral girdle?
This collection of joints connects the scapula, clavicle and humerus. The clavicle is the only bony connection to the
axial skeleton. Full range of motion requires involvement of multiple joints.
what is the main purpose of the acromioclavicular joint?
stabilization
what is the main purpose of the glenohumeral joint?
ROM
What is the main thing to remember about the sternoclavicular joint?
only articulation with axial skeleton
what do the extrinsic muscles of the pectoral girdle do?
connect upper extremities to axial skeleton
What do the intrinsic muscles of the pectoral girdle do?
connect clavicle or scapula to humerus
What is muscle synergy?
Synergy is multiple muscles acting together toward a desired action. They can perform the same action or they can cancel out the unwanted actions.
Describe synergistic relationship between lat dorsi and teres major
the lat dorsi and teres major muscles both act to extend, adduct, and inwardly rotate the humerus.
Describe the synergistic relationship between the trapezius and rhomboids
Trapezius & rhomboids act to retract and elevate the scapula. The trap upwardly rotates while the rhomboids downwardly rotate, so acting together they just elevate and retract.
Describe the synergistic relationship between the serratus anterior and pec minor
Serratus anterior and pec minor both protract scapula, but serratus anterior upwardly rotates while pec minor downardly rotates. The rotations cancel each other out and the result is protraction.
describe the synergistic relationship between the serratus anterior and trapezius
Trapezius and serratus anterior strongly upwardly rotate scapula. ability of serratus to protract the scapula is canceled out by ability of trap to retract scapula.
Describe the muscles involved in full abduction of the humerus
initiation is a function of the supraspinatus. weakness of this muscle results in patient having to “swing” their arm outward from their side to start abduction. Bringing the arm to horizontal (shoulder level) requires the action of the deltoid. Completing the abduction to 180 degrees requires the synergistic action of the deltoid, trapezius, and serratus anterior.
During which movement is scapulohumeral rhythm best seen? Explain.
full abduction of the humerus. The deltoid is responsible for abducting the humerus. However, the humerus would not be able to move upwards because of the acromnion, so the scapular has to be rotated upwards as the humerus is being abducted. The combined actions of the trap and serratus anterior allow for the upward rotation. Damage to either the serratus anterior or the trapezius results in the person not being able to fully abduct the arm, despite the fact that the deltoid is working.
What are the borders and significance of the triangle of auscultation?
borders: lat dorsi, lower trap, and rhomboid major/scapula
floor: 6th and 7th ribs and intercostal space
purpose: listening to thorax
what are borders and contents of triangular space?
borders: teres minor and major, long head of triceps.
contents: transmits branch of circumflex scapular artery.
what are borders and contents of quadrangular space?
borders: teres minor and major, long head of triceps, and humerus. Contents: transmits axillary nerve and posterior humeral circumflex artery.
What are the intrinsic muscles of the shoulder region?
deltoid, teres major, rotator cuff (supraspinatus, infraspinatus, teres minor, subscapularis), pectoralis major
Which muscle is responsible for the roundness of the shoulder?
deltoid
What are the muscles of the rotator cuff?
supraspinatus, infraspinatus, teres minor, subscapularis
What is the rotator cuff?
4 muscles that arise from scapula and insert into the greater and lesser tubercles of humerus. they act to rotate the humerus and provide a major source of active stability to this joint. keep the head of the humerus applied directly to the glenoid fossa and pull the head of the humerus downward. counteract the tendency of the head of the humerus to move up towards the acromion and compress the structures between humeral head and acromion.
Why does the action of the pectoralis major often result in passive protraction of the scapula?
when the humerus moves forward and toward the midline as happens when shoulder is adducted and flexed, scapula is passively pulled away from the midline. results in increasing the reach of the flexed and adducted humerus.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the dorsal scapular nerve?
originates off the root, contribution from C5 and frequently from C4. It dives posteriorly from the plexus. Innervates the rhomboids and the levator scapulae.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the long thoracic nerve?
originates off the root, contribution from C5, C6, and C7. It pierces the middle scalene and then descends posteriorly on the superficial surface of the serratus anterior, innervates the serratus anterior.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the suprascapular nerve?
off superior trunk, C5 and C6 (frequent contribution from C4), passes laterally across posterior triangle of neck above the bracial plexus through the scapular notch under the superior transverse scapular ligament. innervates the supraspinatus and infraspinatus.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the subclavian nerve?
superior trunk c5 and c6 (frequent contribution from C4), descends posterior to clavicle and anterior to brachial plexus and subclavian artery, innervates subclavius
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the lateral pectoral nerve?
off lateral cord, C5-C6-C7, moves posteriorly to deep surface of pectoral muscles. Innervates pectoralis major.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the medial pectoral nerve?
off medial cord, C8 and T1, passes between axillary artery and vein, pierces pectoralis minor, enters deepy surface of pectoralis major. Innervates pectoralis major and minor.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the medial brachial cutaneous nerve?
off medial cord, C8 and T1, runs along medial side of axillary and brachial veins, innervates skin of medial side of arm.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the median antebrachial cutaneous nerve?
medial cord, C8 and T1, initially runs with ulnar nerve– pierces deep fascia with basilic diving into anterior and posterior branches, innervates skin of medial side of forearm
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the upper subscapular nerve?
posterior cord, C5 and C6, passes posteriorly entering subscapularis, innervates subscapularis
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the thoracodorsal nerve?
posterior cord, C6-C7-C8, arises between the upper and lower subscapular nerves runs interolaterally to latissimus dorsi, innervates latissimus dorsi
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the lower subscapular nerve?
posterior cord, C5 and C6, passes inferolaterally deep to subscapular artery and vein, innervates subscapularis and teres major
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the musculocutaneous nerve?
terminal branch of lateral cord C5-C7, pierces coracobrachialis, descends between biceps brachii and brachialis
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the axillary nerve?
terminal branch of posterior cord, C5-C6, dives posteriorly through the quadrangular space with posterior circumflex humeral artery, winds around surgical neck of humerus deep to the deltoid. Innervates deltoid, teres minor, and the skin of the superloateral arm over deltoid
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the median nerve?
terminal branches of lateral cord (C5-C6-C7), medial cord (C8-T1), descends through arm adjacent to brachial artery, crosses over artery to lie medial to it in cubital fossa. Innervates anterior forearm (except flexor carpi ulnaris an ulnar half of flexor digitoorum profundus), the five intrinsic muscles in thenar half of the palm, and the palmar skin.
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the radial nerve?
terminal branch of posterior cord, C5-C6-C7-C8-T1. Runs posterior to humerus in radial groove with deep brachial artery between lateral and medial head of triceps, enters cubital fossa, divides into superficial (cutaneous) and deep (motor), innervates posterior arm and forearm muscles, skin of posterior and inferolateral arm, skin of posterior forearm, and skin of lateral dorsum of the hand lateral to axial line of digit 4
What is the brachial plexus origin, spinal nerve contribution, course, and innervated muscles of the ulnar nerve?
terminal branches of medial cord (C8-T1), descends medial arm, passes posterior to the medial epicondyle and descends ulnar aspect of forearm to hand, innervates flexor carpi ulnaris, ulnar half of flexor digitorum profundus, intrinsic muscles of the hand, and skin of hand medial to axial line of digit 4.
What nerves originate from the roots of the brachial plexus?
the dorsal scapular and long thoracic
Which nerves originate off the trunks of the brachial plexus?
subclavian and suprascapular
Which nerves originate from the cords of the brachial plexus?
lateral pectoral, medial pectoral, medial brachial cutaneous, median antebrachial cutaneous, upper subscapular, thoracodorsal, and lower subscapular
Which nerves originate from the terminal branches of the brachial plexus?
musculocutaneous, axillary, median, radial, and ulnar
Which nerve passes laterally across the psoterior triangle of the neck?
suprascapular
Which nerve passes between the axillary artery and vein?
medial pectoral
which nerve pierces the pectoralis minor before entering the deep surface of the pectoralis major?
medial pectoral
which nerve moves posteriorly to the deep surface of the pectoral muscles?
lateral pectoral
Which nerve runs along the medial side of the axillary and brachial veins?
medial brachial cutaneous
which nerve initially runs with the ulnar nerve before piercing the deep fascia with the basilic vein?
median antebrachial cutaneous
which nerve pierces the coracobrachialis?
musculocutaneous
Which nerve dives posteriorly through the quadrangular space with the posterior circumflex humeral artery?
axillary
Which nerve descends adjacent to the brachial artery anteriorly?
median
Which nerve runs with the deep brachial artery anteriorly?
radial
Which nerve tucks behind the medial epicondyle?
ulnar
Which nerves originate from the divisions of the brachial plexus?
none
