·
Clavicle is the first bone to begin ossification
during fetal development, but it is the last one to complete ossification, at about age 21
years.
·
Boxer's fracture: is a fracture of the necks
of the second and third metacarpals, seen in professional boxers, and typically
of the fifth
metacarpal in unskilled boxers.
·
Rupture of rotator cuff may occur by a chronic
wear and tear or an acute fall on the outstretched arm and is manifested by
severe limitation of shoulder joint motion but chiefly abduction. A rupture of
the rotator cuff, particularly attrition of the supraspinatus tendon by friction among middle-aged persons,
ultimately causes degenerative inflammatory changes (degenerative tendonitis)
of the rotator cuff, or this attrition of the supraspinatus tendon and the
underlying joint capsule leads to an open communication between the shoulder
joint cavity and the subacromial bursa, which is subject to inflammation
(subacromial bursitis and supraspinatus tendinitis), resulting in a painful abduction of the arm or a painful
shoulder.
·
The suspensory ligament of the axilla, which
is the inferior extension of the Clavipectoral fascia and is attached to the
axillary fascia, maintaining the hollow of the armpit.
·
Teres Major – Lower Subscapular Nerve
Teres Minor – Axillary Nerve
·
A. Quadrangular space is bounded superiorly by
the teres minor and subscapularis muscles, inferiorly by the teres major
muscle, medially by the long head of the triceps, and laterally by the surgical
neck of the humerus. Transmits the axillary nerve and the posterior humeral
circumflex vessels.
B. Triangular space (upper) is bounded superiorly
by the teres minor muscle, inferiorly by the teres
major muscle, and laterally
by the long head of the triceps. Contains the circumflex scapular vessels.
C. Triangular space (lower) is formed superiorly
by the teres major muscle, medially by the long head of the triceps, and
laterally by the medial head of the triceps. Contains the radial nerve and the
profunda brachii (deep brachial) artery.
·
Anatomic snuffbox is a triangular interval
bounded medially by the tendon of
the extensor pollicis longus muscle and
laterally by the tendons of the extensor pollicis brevis and abductor
pollicis longus muscles.
·
Flexor retinaculum is crossed superficially by
the ulnar nerve, ulnar artery, palmaris longus tendon, and palmar cutaneous
branch of the median nerve.
·
Mallet finger (Hammer or baseball finger): is
a finger with permanent flexion of the distal phalanx due to an avulsion of the
medial and lateral bands of the extensor tendon to the distal phalanx.
·
Boutonniere deformity: is a finger with
abnormal flexion of the middle phalanx and hyperextension of the distal phalanx
due to an avulsion of the central band of the extensor tendon to the middle
phalanx or rheumatoid arthritis.
·
Injury to
the posterior cord: is caused by the pressure of the crosspiece of a
crutch, resulting in paralysis of the arm called crutch palsy.
·
Nerve to subclavius (C5) usually branches to the
accessory
phrenic nerve (C5), which enters the thorax to join the phrenic
nerve.
·
Thoracoacromial artery branches"CAlifornia Police Department": Clavicular Acromial Pectoral Deltoid
·
Anterior forearm muscles: superficial
groupThere are five, like
five digits of your hand. Place your thumb into your palm, then lay that hand
palm down on your other arm, as shown in diagram. Your 4 fingers now show
distribution: spells PFPF [pass/fail, pass/fail]: Pronator teres Flexor carpi radialis Palmaris
longus Flexor carpi ulnaris Your
thumb below your 4 fingers shows the muscle which is deep to the other four:
Flexor digitorum superficialis.
·
Intrinsic muscles of hand
(palmar surface) "A OF A OF A":
· Thenar, lateral to medial:
Abductor pollicis longus
Opponens pollicis
Flexor pollicis brevis
Adductor pollicis.
· Hypothenar, lateral to medial:
Opponens digiti minimi
Flexor digiti minimi
Abductor digiti minimi
· Thenar, lateral to medial:
Abductor pollicis longus
Opponens pollicis
Flexor pollicis brevis
Adductor pollicis.
· Hypothenar, lateral to medial:
Opponens digiti minimi
Flexor digiti minimi
Abductor digiti minimi
Oppose, Abduct, and Flex
(OAF) same kind of action.
·
No palmar
interosseous muscle is attached to the middle digit.
·
The opponens
pollicis inserts on the first metacarpal. All other intrinsic muscles of the
thumb, including the abductor pollicis brevis, the flexor pollicis brevis, and
the adductor pollicis muscles, insert on the proximal phalanges.
·
The ulnar bursa, or
common synovial flexor sheath, contains the tendons of both the flexor
digitorum superficialis and profundus muscles. The radial bursa envelops the
tendon of the flexor pollicis longus. The tendons of the flexor carpi ulnaris
and the palmaris longus are not contained in the ulnar bursa.
·
The posterior
humeral circumflex artery anastomoses with an ascending branch of the profunda
brachii artery, whereas the lateral thoracic and subscapular arteries do not.
The superior ulnar collateral and radial recurrent arteries arise inferior to
the origin of the profunda brachii artery.
·
The anterior
interosseous nerve is a branch of the median nerve and supplies the flexor
pollicis longus, half of the flexor digitorum profundus, and the pronator
quadratus. The median nerve supplies the pronator teres, flexor digitorum
superficialis, palmaris longus, and flexor carpi radialis muscles. A muscular
branch (the recurrent branch) of the median nerve innervates the thenar
muscles.
·
The little finger
has no attachment for the dorsal interosseous muscle because it has its own
abductor.
·
The subscapularis
muscle inserts on the lesser tubercle of the humerus. The supraspinatus,
infraspinatus, and teres minor muscles insert on the greater tubercle of the
humerus. The coracohumeral ligament attaches to the greater tubercle.
·
The ulnar nerve
innervates the adductor pollicis muscle. The radial nerve innervates the
abductor pollicis longus and extensor pollicis brevis muscles, whereas the
median nerve innervates the abductor pollicis brevis and opponens pollicis
muscles.
·
The
intercostobrachial nerve arises from the lateral cutaneous branch of the second
intercostal nerve and pierces the intercostal and serratus anterior muscles. It
may communicate with the medial brachial cutaneous nerve, and it supplies skin
on the medial side of the arm. It contains no skeletal motor fibers but does
contain sympathetic postganglionic fibers, which supply sweat glands.
·
The upper and
lower subscapular nerves innervate the
subscapularis muscle, which is the only muscle of the rotator cuff group that
medially rotates the arm. The lower subscapular nerve also innervates
the teres major muscle, which is not part of the rotator cuff group. The suprascapular
nerve innervates the supraspinatus and infraspinatus muscles that abduct and
laterally rotate the arm, respectively. The teres minor muscle, innervated by
the axillary nerve, also laterally rotates the arm. The thoracodorsal
nerve, originating from the posterior cord between the upper and lower
subscapular nerves, innervates the latissimus dorsi muscle.
·
The flexor pollicis brevis has two heads and
there is a sesamoid bone associated with each of the tendons of these heads.
Sesamoid bones are isolated islands of bone that may occur in tendons passing
over joints. The patella is the classic example. The adductor pollicis also has two heads (transverse and oblique), but
they are not associated with sesamoid bones.
·
The deep radial nerve passes between the deep and
superficial layers of the supinator muscle and lies on a bare area of the
radius where it may be compressed by action of the supinator or damaged by a
fracture of the radius.
·
Clavicle fracture is relatively common––brachial plexus is protected from
injury by subclavius muscle.
·
Pronator Syndrome: In the proximal forearm, the median nerve may be
compressed at the fibrous arch between the two heads of the FDS, the two heads
of the pronator teres, the lacertus fibrosis (bicipital aponeurosis at the
elbow), and the ligament of Struthers. Compression at any or all of these sites
is loosely grouped under the pronator syndrome. The
symptoms produced are similar to those of carpal tunnel, although nocturnal
symptoms are uncommon. The palm may also feel numb because the palmar cutaneous
branch is involved, but is specifically spared in carpal tunnel syndrome because that nerve branch passes superficial to the
flexor retinaculum and arises proximal to the retinaculum. Symptoms may be
reproduced or worsened by attempting pronation against resistance and by
resisted flexion of the middle finger. However, it may be difficult to
precisely locate the compressive cause in the pronator syndrome, and surgical
decompression often involves release of all four potential sites of
compression.
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