Hand

Everything in anatomical position, which is supinated hands at side. Palm forward.

 
 

'' means same as above

 
 

MP-metacarpophalangeal

Cm- Carpometaphalangeal

Bony anatomy

Wrist Bone- Carpals

• Organized into two rows with 4 columns
  
• Right Hand in anatomical position
  
• 
  

Hamate	Capitate	Trapezoid	Trapezium (articulates with thumb)
Pistiform	Triquetrum	Lunate	Scaphoid

• Mnemonic:
  

  Some Lovers Try Positions That They Can't Handle." Starting from the thumb, the eight carpal bones are Scaphoid, Lunate, Triquetrum, Pisiform, Trapezium, Trapezoid, Capitate, and Hamate. To tell the three T's apart... triquetrum has "tri/try" in it, and trapezium and trapezoid are in alphabetical order.
  

   
   

Distal Row

 
 

Proximal Row

 
 

Distal phalanx

 
 

Intermediate Phalanx

 
 

Proximal Phalanx

 
 

Numbering system- One is the thumb (Rhymes)

 
 

Actions of Thumb-

Counter intuitive, but just remember that flexion and opposition of thumb are closely related (in opposition you actually touch another finger, extension you don't). Therefore extension is away from middle finger (in anatomical position).

 
 

Actions of other fingers-

Moving fingers away from middle finger extended line, abduction. Middle finger can't aDduct bc it has to move away from line.

 
 

Flexion- Curl fingers up into fist

Extension- move em other way.

 
 

Compartments of Hand

Most superficial (anatomical pos)

Base of thumb- Thenar compartment

Base of pinky- hypothenar (hypo- means less, pinky has less mass than thumb)

In between these two- central compartment (center of hand)

Deep

Interosseous compartments- between metacarpals

Adductor comparment- deep to the thenar comparmtnet.

 
 

If you take off the palm Hannibal-Lector Style, you see the palmar aponeurosis, dense connective tissue

Abnormal thickening,shortening, fibrosis of this band- Dupuytren Contracture

Fingers pulls in to flexion (fist)

Multiple Surgeries to correct

Usually happens to men, some genetic basis

 

Thenar (Thumb) Intrinsic muscles of hand (chicken drumstick muscle)

Muscle	Origin	Insertion	Innervation	Action
Abductor pollicis brevis	Flexor Retinaculum, trapezum, scaphoid.	Base of proximal phalanx of Thumb	Recurrent branch of median nerve (C8,T1)	Abducts thumb, helps to oppose thumbs
Flexor pollicis brevis	''	''	''	Flexs thumb at MC and MP joints
Deep to above muscles: Opponens policis	''	I Don't know, she didn't say	''	Opposes thumb at 1st Carpometacarpal joints

 
 

Hypothenar compt. (Pinky) intrinsic muscles of hand

Pretty much mirror image of thumb intrinsic muscles except pollicis= digit minimi

 
 

Muscle	Origin	Insertion	Innervation	Action
Abductor digiti minimi			Deep branch of ulnar n. (C8,T1)	Abducts at MP
Flexor digiti minimi brevis			''	Flexes V @ MP, PIP
Opponens digiti minimi			''	Opposes V @ MP

 
 

Adductor compartment

Muscle	Origin	Insertion	Innervation	Action
Adductor policis (two heads Transverse			Deep branch of ulnar muscle ( exception bc all other thenar are innervated by median n. recurrent branch)	Adduct thumb @ MP joint

 
 

Central compartment

Weird bc lumbrical attach tendon to bone not bone to bone.

Muscle	Origin	Insertion	Innervation	Action
Lumbrical (1-4) "Bye-bye muscles"			1st & 2nd- Median n. (C& T1) 3rd & 4th- Deep branch of ulnar nerve	Flex MP (all fingers except thumb) Extend MP( all fingers except thumb)

 
 

 
 

FYI: It is impt to think about these muscles in term of compartments, otherwise it seems really random.

Remember hypothenar is on the superficial pinky side, thenar is on the thumb side, central between.

Deep: Adductor deep to thenar and interosseous between metacarpals.

 
 

Interosseus Cmpt (deep to lumbricals)

Muscle	Origin	Insertion	Innervation	Action
Dorsal interossei	Didn't even see on slide		Deep branch of ulnar (C8,TI)	DAB- Dorsal abduct II,III,IV, Help lumbricals flex MP and ext. IP ts
Palmar Interossei			''	PAD- Palmar Adduct II, IV, V, Help lumbircals flex MP and ext. IP joints

 
 

 
 

 
 

 
 

Common finger injuries

 
 

Skier's thumb:

 
 

Mallet thumb:

 
 

Boutonniere Deformity:

Swan-neck Deformity

 
 

 
 

 
 

Swan-neck Deformity

Mechanism of Injury:

• Rheumatoid arthritis, trauma from fall
  
  • Dorsal dislocation of middle phalanx
    
  • May damage joint ligaments
    

  Presentation:
  

  
  

• Hyperextension at PIP, hyperflexion of DIP
  
• Severely limits function
  

   
   

  
  

   
   

   
   

  Once ulnar hits palm goes to deep and superficial branch.
  

   
   

  Carpal Tunnel injury
  

  Bone and dense connective tissue. Space cannot expand. What's in tunnel? All tendons that flex fingers. And the Median nerve. That gets compressed bc space cannot expand. If median nerve compressed? Both motor and sensory functions
  

   
   

  
  

  Mechanism of injury
  

• Inflammation of FDS/FDP/FPL tendons or sheaths, fluid retention, infection
  
• Compression of median nerve (poor bacha)
  

   
   

  Presentation:
  

• Paresthesia, hypoesthesia, anesthesia over lateral 3½ digits (IN ANATOMICAL POS)
  
• Progressive weakness of abductor pollicis brevis & opponens pollicis mm.
  
  • Inability to oppose thumb, difficulty gripping objects in hand
    

   
   

  Distal Median N. Injury
  

  Mechanism of Injury:
  

• Damage to the distal median n./recurrent branch of median n.
  
  • Attempted suicide by wrist slashing, 'bagel cutting' injury
    

  Presentation:
  

• Paralysis of thenar mm. (Simian "Ape" Hand), lumbricals 1-2
  
  • Inability to oppose thumb, limited abduction of thumb
    

    (thumb moves mainly in flexion/extension)
    

  • Loss of fine control in digits II-III
    

   
   

  Suicide can present with median nerve damage similar to
  

  Thenar nerve- Very superficial not well protected.
  

  Ape hand- can still do flexion and extension, but can't oppose.
  

   
   

   
   

   
   

  Ulnar Canal Syndrome ("Guyon Tunnel Syndrome")
  

  Mechanism of Injury:
  

• Compression of ulnar nerve in ulnar (Guyon's) canal
  
  • Pressure against handelbar, carpal fracture, thrombus
    

  Presentation:
  

• Paresthesia, hypoesthesia, anesthesia over medial 1½ digits
  
• Progressive weakness of lumbricals (3^rd-4^th) and interossei mm.
  
  • Clawing of digits IV-V
    

   
   

   
   

  
  

   
   

   
   

   
   

  Blood Supply to hand
  

   
   

  
  

   
   

  
  

   
   

  
  

   
   

Pollicis means thumb

Should be @ CM and MP joints

 
 

 
 

Mechanism of inj: fall onto outstretch hand w obj in palm (ie ski pole

Result: Torn, stretch ulnar collateral ligament

Presentation: Pain, swelling at base of thumb. Weakness/inability to grasp.

 
 

Mechanism of inj: direct blow to distal phalanx

Result: extensor digitorum tendon avulsed from distal phalanx

Presentation: Hyper extended DIP

 
 

Boutonnière Deformity

Mechanism of Injury:

• Rheumatoid arthritis, trauma from fall
  
  • Palmar dislocation of middle phalanx
    
  • May avulse extensor digitorum tendon
    

  Presentation:
  

• Hyperflexion at PIP
  
• Severely limits function