Lecture Review

• why is the palm so sensitive

  tactile sensation

  large region of the somatosensory cortex devoted to sensation in the hand
• what sensory innervates the lateral palm?

  median n.
• what nerve does sensory innervation of the medial palm and dorsum and digits 4.5-5?

  ulnar n.
• where does the radial n. contribute sensory innervation?

  lateral dorsum of the hand
• what are the 5 compartments of the hand intrinsic muscles

  thenar eminence (3 muscles)

  adductor compartment (1 muscle)

  hypothenar eminence (3 muscles)

  short muscles of the hand (lumbricals)

  interosseous compartment (4 dorsal and 3 palmar)
• what nerve innervates the thenar eminence?

  recurrent median nerve
• what muscles make up the thenar muscles?

  flexor pollicis brevis

  abductor pollicis brevis

  opponens pollicis
• what nerve innervates the adductor pollicis?

  ulnar nerve (deep branch)
• what are the origins of the adductor pollicis heads?

  oblique head: capitate, 2nd and 3rd metacarpals

  transverse head: 3rd metacarpal
• what are the hypothenar muscles

  flexor digiti minimi brevis

  abductor digiti minimi brevis (most medial)

  opponens digiti mini

  all originate from the pisiform/hook of hamate and insert on digit 5 metacarpal or proximal phalanx

  all are innervated by the deep branch of the ulnar n.
• lumbricals

  flex digits 2-5 at the MCP joint and extend the digits at the IP joints
• interossei

  DAB (dorsal abduct digits 2 and 4 and act with lumbricals to flex and extend)

  PAD (palmar adduct digits 2, 4, and 5 and act with lumbricals)

  innervated by ulnar nerve (deep branch)
• what is the purpose of intertendinous connections?

  prevent individual extension
• ulnar nerve injury causes what

  ulnar claw

  flexion of the IP joints is weakened
• what is the ulnar paradox

  ulnar nerve lesion occurs more proximal
• what does a median nerve injury cause?

  inability to flex index finger at the MCP and IP joints

  due to loss of lateral lumbricals

  benediction hand (seen when trying to make a fist): more of a pinching motion while trying to grab
• symptoms of rheumatoid arthritis (RA)

  ulnar deviation of the MCPs

  prolonged morning stiffness
• osteoarthritis (OA) findings

  Herberden nodes (osteophytes of DIP joints)

  Bouchard nodes (Osteophytes of the PIP joints)
• what is hyperflexion of the DIP joint called?

  mallet finger (baseball finger)

  tearing the extensor mechanism as it inserts on the distal phalanx
• boutonniere's deformity vs. swan neck

  boutonniere's: ruptured central slip (DIP extension)

  swan neck: ruptured volar plate (DIP flexion)
• what tendons are involved in de quervian's tenosynovitis and what are other common names?

  abductor pollicis longus and the extensor pollicis brevis

  gamer's thumb or texting thumb"
• triangular fibrocartilage complex (TFCC)

  ligament between ulna/ lunate/ triquetrum
• what muscle makes up the anterior intermediate layer of the forearm

  flexor digitorum superficialis that is innervated by the median nerve
• cubital tunnel syndrome

  compression of the ulnar nerve in the cubital tunnel

  causes: numbness and tingling in digits 4-5

  weakness in ulnar deviation
• 1/3 of nerve injuries in the UE affect what nerve

  ulnar nerve
• common origin, innervation, and action of the posterior superficial layer of the forearm

  lateral epicondyle or supraepicondylar ridge

  radial nerve

  extension of wrist and digits
• muscles that make up the posterior superficial layer of the forearm

  brachioradialis (only elbow flexor not innervated by musculocutaneous n.)

  extensor carpi radialis longus

  extensor carpi radialis brevis
• lateral epicondylitis "tennis elbow"


  smalls tears in the tendon of the ECRB lead to inflammation

  can also affect the periosteum of the lateral epicondyle

  pain with wrist extension
• what muscles contribute to radial deviation

  extensor carpi radialis longus

  extensor carpi radialis brevis

  flexor carpi radialis
• insertion for all extensor tendons, lumbricals, interosseous m.

  extensor expansion
• anatomical snuffbox is made up of what

  extensor pollicis longus tendon

  abductor pollicis longus tendon

  extensor pollicis brevis tendon
• anterior compartment of the arm is responsible for what motions

  flexors/ supinators
• primary elbow flexor

  brachialis

  biceps brachii (supination and flexion)
• brachioradialis innervation

  radial n. (allows flexion if median. is injured)
• brachial a. is a continuation of what a.?

  axillary a.
• branches of the brachial a.

  deep brachial a. (supplies posterior compartment)

  humeral nutrient a.

  superior and inferior ulnar collateral arteries
• triceps brachii inserts on

  olecranon
• triceps brachii action

  forearm extension, long head does arm extenion
• innervation of the triceps brachii

  radial n.
• origins of the triceps brachii heads

  Long head: infraglenoid tubercle

  medial and lateral heads: posterior humeral