Upper limb anatomy Flashcards
How are muscles in the arm and forearm separated?
Muscles in the arm and forearm are separated into anterior (flexor) and posterior (extensor) compartments by layers of fascia, bones, and ligaments
….muscles in the anterior compartment of the arm are innervated by the …. nerve.
All muscles in the anterior compartment of the arm are innervated by the musculocutaneous nerve.
Which muscles are innervated by the median nerve?
The median nerve innervates the muscles in the anterior compartment of the forearm, with two exceptions—one flexor of the wrist (the flexor carpi ulnaris muscle) and part of one flexor of the fingers (the medial half of the flexor digitorum profundus muscle) are innervated by the ulnar nerve.
Which nerve supplies the intrinsic muscles of the hand?
Most intrinsic muscles of the hand are innervated by the ulnar nerve, except for the thenar muscles and two lateral lumbrical muscles, which are innervated by the median nerve.
Which nerve supplies the posterior compartment of the arm and forearm?
Radial n.
Where does the axillary nerve come into contact with the humerus?
supplies the deltoid muscle, a major abductor of the humerus at the glenohumeral joint, passes around the posterior aspect of the upper part of the humerus (the surgical neck).
Where does the radial nerve come into contact with the humerus?
which supplies all of the extensor muscles of the upper limb, passes diagonally around the posterior surface of the middle of the humerus in the radial groove.
Where does the ulnar nerve come into contact with the humerus?
The ulnar nerve, which is ultimately destined for the hand, passes posteriorly to a bony protrusion, the medial epicondyle, on the medial side of the distal end of the humerus.
What are the superficial muscles of the shoulder?
The superficial muscles of the shoulder consist of the trapezius and deltoid muscles, which together form the smooth muscular contour over the lateral part of the shoulder. These muscles connect the scapula and clavicle to the trunk and to the arm, respectively.
What part of the humerus is most susceptible to injury?
The axillary nerve and the posterior circumflex humeral artery, which pass into the deltoid region from the axilla, do so immediately posterior to the surgical neck. Because the surgical neck is weaker than more proximal regions of the bone, it is one of the sites where the humerus commonly fractures.
What is the origin of the trapezius muscle?
Superior nuchal line, external occipital protuberance, medial margin of the ligamentum nuchae, spinous processes of C7 to T12 and the related supraspinous ligaments
What is the origin of the deltoid muscle?
Inferior edge of the crest of the spine of the scapula, lateral margin of the acromion, anterior border of lateral one-third of clavicle
Innervation of trapezius?
Motor spinal part of accessory nerve (XI). Sensory (proprioception) anterior rami of C3 and C4
Innervation of deltoid?
Axillary nerve (C5, C6)
Innervation of levator scapulae
Branches directly from anterior rami of C3 and C4 spinal nerves and by branches (C5) from the dorsal scapular nerve
Innervation of rhomboid minor and major?
Dorsal scapular nerve (C4, C5)
Function of deltoid muscle?
Major abductor of arm (abducts arm beyond initial 15° done by supraspinatus); clavicular fibers assist in flexing the arm; posterior fibers assist in extending the arm
Function of trapezius muscle
Powerful elevator of the scapula; rotates the scapula during abduction of humerus above horizontal; middle fibers retract scapula; lower fibers depress scapula
Function of rhomboid major and minor?
Elevates and retracts the scapula
Function of levator scapulae
Elevates the scapula
What muscles make up the posterior scapula region?
The posterior scapular region occupies the posterior aspect of the scapula and is located deep to the trapezius and deltoid muscles. It contains four muscles, which pass between the scapula and proximal end of the humerus:
supraspinatus,
infraspinatus,
teres minor, and teres major muscles.
Innervation of the long head of triceps brachii
Radial nerve (C6, C7, C8)
Which ligaments are likely to be torn when the acromio-clavicular joint is dislocated?
Coracoclavicular ligaments – has 2 parts conoid and trapezoid
The joint capsule of the acromioclavicular joint and any ligamentous thickenings can also be torn
What deformity will you be able to see following the injury? ( Pratheep has fallen from his skateboard hitting his shoulder hard against the ground. Pratheep is later diagnosed with a dislocated acromioclavicular joint.)
The distal end of the clavicle will sit superior to the acromion where it is observable and palpable
Why is injury of the acromio-clavicular joint often called a “shoulder separation”.
The term shoulder separation is really a misnomer. It refers to the fact that the shoulder joint has separated from the supporting strut that is the clavicle. Separation can refer to a subluxation or dislocation of the joint.
[Several weeks after surgical resection of the right axillary lymph nodes (performed for the staging and treatment of breast cancer), Mary’s husband noticed that her right scapula was sticking out more than the left.]
Which nerve was damaged during the nodal resection?
Long thoracic nerve as it passes inferiorly through the axilla over the superficial surface of serratus anterior
What is the abnormality commonly called and how would you test the function of the nerve during examination of the patient?
[Several weeks after surgical resection of the right axillary lymph nodes (performed for the staging and treatment of breast cancer), Mary’s husband noticed that her right scapula was sticking out more than the left.]
Winging of the scapula.
Patient faces a wall, places palms of hands on the wall, lock the arms in an extended position
and then leans into the wall (almost like doing the first stage of press up into the wall). Serratus anterior contraction should prevent scapula winging.
