MSK: Anatomy Flashcards
What are tubercles, tuberosities, and trochanters, condyles, and epicondyles?
Rounded projections of bone.
Condyles and epicondyles are at the articulating end.
Name 6 types of synovial joints.
Pivot
Hinge
Saddle
Ball-and-socket
Condyloid
Plane
What is the difference between the origin and insertion of a muscle?
The origin is the attachment site that doesn’t move during contraction, while the insertion is the attachment site that does move when the muscle contracts.
What are the main branches of the main upper limb arteries?
Subclavian artery -> axillary -> brachial -> radial & ulna.
What are the main branches of the main lower limb arteries?
Common iliac artery -> external iliac -> femoral -> popliteal -> tibial/fibula
What type of joint is the glenohumeral joint, and what two bones form this joint?
Synovial ball and socket joint.
Scapula and humerus.
What type of joint is the elbow?
Synovial hinge joint.
What joint is formed by the articulation between the distal radius and two of the carpal bones? What type of joint is this?
Radiocarpal joint.
Synovial condyloid joint.
What is protraction and retraction of the scapula?
Protraction = moving anteriorly e.g. reaching forwards
Retraction = moving posteriorly e.g. pulling shoulder back
What articulation is found at the proximal/medial end of the clavicle?
Clavicle articulates with the manubrium of the sternum (sternocalvicular joint).
What articulation is found at the distal/lateral end of the clavicle?
Clavicle articulates with the acromion of the scapula (acromiovlavicular joint).
What ridge is palpable on the posterior surface of the scapula?
The spine
What does the lateral end of the spine of the scapula expand to form?
The acromion
What ‘beak-like’ projection of the scapula sits inferior to the acromion on the anterior surface of the scapula, and provides the site of attachment for several muscles?
Coracoid process (Greek: ‘raven-like’)
What structures form the pectoral girdle?
Clavicle, scapula, and attached muscles.
What part of the lateral aspect of the scapula does the head of the humerus articulate with at the glenohumeral joint?
Glenoid fossa
What two small projections of bone superior and inferior to the glenoid fossa of the scapula are important sites for muscle attachments?
Supraglenoid and infraglenoid tubercles.
What two projections of bone on the proximal humerus provide important sites for muscle attachment?
Greater and lesser tubercles.
Why can fractures of the surgical neck of the humerus or shoulder dislocations cause numbness/weakness in the affected arm?
The axillary nerve runs medially to the surgical neck of the humerus. Anterior shoulder dislocation can put pressure on and potentially damage the axillary nerve.
What slight protuberance of the upper lateral aspect of the humeral shaft is an important site of muscle attachment?
Deltoid tuberosity (attachment of deltoid muscle).
Why can mid-shaft humeral fractures damage the radial nerve?
The radial (or spiral) groove runs along the posterior aspect of the humeral shaft and can be injured in mid-shaft humeral fractures.
What important movement is the scapula capable of which allows the arm to be raised above the head?
Rotation.
What large superficial muscle of the posterior pectoral girdle attach the scapula to the skull, cervical, and thoracic vertebrae?
What four movements does contraction of this muscle allow in the scapula?
Trapezius.
Rotation, elevation, retraction, depresses.
What are the three smaller deeper muscles of the posterior pectoral girdle, that attach the scapula to the vertebral column?
Levator scapulae
Rhomboid major
Rhomboid minor
Contraction of what two small deep muscles of the posterior pectoral girdle, that attach the medial border of the scapula to the vertebral column, cause retraction of the scapula?
Rhomboid major (C7 and T1 origin)
Rhomboid minor (thoracic vertebrae origin)
What large superficial muscle of the posterior pectoral girdle, originates from the lower thoracic vertebrae and inserts onto the humerus, and causes extension, adduction, and internal rotation of the humerus?
Latissimus dorsi.
Most of the muscles of the posterior pectoral girdle are innervated by branches of the brachial plexus.
What nerve innervates the trapezius muscle?
Accessory nerve (CN VI) - NOT the brachial plexus!
What branch of the brachial plexus innervates the latissimus dorsi muscle of the posterior pectoral girdle?
Thoracodorsal nerve.
What six muscles attach the scapula to the humerus to move and stabilise the shoulder joint?
Deltoid
Supraspinatus
Infraspinatus
Subscapularis
Teres minor
Teres major
What four muscles have tendons which fuse with the fibrous capsule that surrounds the shoulder joint, working together to form the stabilising rotator cuff?
Supraspinatus
Infraspinatus
Teres minor
Subscapularis
(“SITS”)
What three bones does the deltoid muscle attach to?
Lateral part of the clavicle
Spine of the scapula
Humerus
What branch of the brachial plexus innervates the deltoid muscle?
Axillary nerve.
What muscle is a powerful abductor of the shoulder joint, but cannot initiate abduction?
Deltoid
What muscle initiates abduction of the shoulder?
Supraspinatus
The tendon of what muscle can be inflamed and pinched between the acromion and the humerus during shoulder movements (impingement)?
Supraspinatus
The axillary nerve travels through the quadrilateral space to enter the posterior scapula region.
What four structures form the boundaries of the quadrilateral space?
Teres minor (superior)
Teres major (inferior)
Long head of the triceps (medial)
Surgical neck of the humerus (lateral)
Other than the rotator cuff muscles, what three structures help stabilise the shoulder joint?
Glenoid labrum (rim of fibrocartilage around margin of glenoid fossa)
Ligaments
Tendon of biceps brachii
There are five groups of lymph nodes in the axilla that drain the upper limb, breast, chest wall, scapular region, and abdominal wall.
What lymph nodes in the apex of the axilla receive lymph from all these other lymph nodes?
Apical nodes
The subclavian artery travels over the first rib and under the clavicle into the axilla.
When does the subclavian artery become the axillary artery?
After it passes over the lateral border of the first rib.
When does the axillary artery become the brachial artery?
When it crosses the inferior border of teres major.
The brachail and basilic veins join to form the axillary vein, and the cephalic vein also joins in the axilla.
When does the axillary vein become the subclavian vein?
At the lateral border of the first rib.
What four bony prominences are found on the distal end of the humerus?
Medial and lateral epicondyles.
Trochlea
Capitellum
What does the trochlea, a bony prominence on the distal end of the humerus, articulate with?
The trochlear notch of the ulna.
What does the capitellum, a bony prominence on the distal end of the humerus, articulate with?
Head of the radius.
What separates the anterior and posterior compartments of the arm?
Intermuscular septa (which extend from the deep brachial fascia which surrounds the arm).
What three flexor muscles are found in the anterior compartment of the arm?
What nerve innervates them?
Biceps brachii
Brachialis
Coracobrachialis
Musculocutaneous nerve
What do the long and short head of the biceps brachii attach to both proximally and distally?
Proximally:
Long head - supraglenoid tubercle
Short head - coracoid process
Distally:
Converge to insert via a common tendon onto the radial tuberosity of the radius.
What movement can the biceps help with when the elbow is flexed?
Supination of the forearm.
What muscle attaches to the anterior aspect of the distal half of the humeral shaft, and inserts distally upon the ulna tuberosity to work as a powerful flexor of the elbow?
Brachialis
What are the three origin sites of the triceps brachii muscle in the posterior compartment of the arm?
Long head: infraglenoid tubercle of the scapula.
Lateral head: posterior humerus (proximal to radial groove).
Medial head: posterior humerus (distal to radial groove).
What is the most medial part of the triceps brachii?
Long head of the triceps.
The three muscle bellies of the triceps brachii converge via a common tendon onto a single insertion point. What is this insertion point?
Olecranon of the ulna.
What innervates all three parts of the triceps brachii?
Radial nerve.
What five spinal nerves are the roots of the brachial plexus, providing motor and sensory fibres to the upper limb?
C5, C6, C7, C8, T1
What two spinal nerve roots combine to form the superior trunk of the brachial plexus?
C5 and C6
What two spinal nerve roots combine to form the inferior trunk of the brachial plexus?
C8 and T1
What spinal nerve roots form the middle trunk of the brachial plexus?
C7
What happens to the three trunks of the brachial plexus under the clavicle?
Each trunk divides into an anterior and posterior division.
Posterior divisions of all the trunks of the brachial plexus combine to form what main cord?
The posterior cord.
What cord does the anterior division of the inferior trunk of the brachial plexus become?
The medial cord.
The anterior divisions of the superior and middle trunks of the brachial plexus combine to form what cord?
The lateral cord.
What are the five major terminal branches of the brachial plexus?
Axillary
Radial
Musculocutaneous
Ulnar
Median
What two branches of the brachial plexus are formed from the posterior cord?
Axillary and radial nerves
What branch of the brachial plexus is formed from a branch of the lateral cord and a branch of the medial cord?
Median nerve
What branch of the brachial plexus is formed from a branch of the lateral cord?
Musculocutaneous nerve
What branch of the brachial plexus is formed from a branch of the medial cord?
Ulnar nerve
What two muscles and areas of skin does the axillary nerve provide motor innervation to?
Deltoid and teres minor.
Also a small region of skin over the upper lateral arm.
What muscles and areas of skin does the radial nerve provide motor innervation to?
Triceps and all the muscles in the posterior compartment of the forearm.
Regions of skin over the arm, forearm, and hand.
What muscles and areas of skin does the musculocutneous nerve innervate?
The three muscles in the anterior compartment of the arm (biceps brachii, brachialis, coracobrachialis).
Skin over the lateral forearm.
What muscles and areas of skin does the median nerve innervate?
The small muscles of the thumb and most of the muscles of the anterior forearm.
Skin over lateral aspect of palm of the hand and the lateral digits.
Where is the median nerve most vulnerable to damage?
As it crosses the anterior aspect of the elbow - the anterior cubital fossa.
What muscles and areas of skin does the ulnar nerve innervate?
Most of the small muscles in the hand.
Skin over the medial aspect of the hand and medial digits.
Where is the ulnar nerve most vulnerable to damage?
Behind the medial epicondyle - easily palpable (“funny bone”).
