Appendicular Skeleton

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Appendicular Skeleton
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Pectoral (Shoulder) Girdle
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Pectoral Girdle

• Attach the bones of the upper limbs to the axial
  skeleton
• Consist of two bones clavicle and scapula
• The joints are freely movable in many directions

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Clavicle

• Also known as the collarbone
• Long, slender S-shaped bone that is horizontally
  above the first rib
• Transmits mechanical force from the upper limb
  to the trunk

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Scapula

• Also known as the shoulder blade
• Large, flat triangular bone situated in the
  posterior part of the thorax

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• A sharp ridge, the spine, runs diagonally across
  the back portion of the scapula body
• The lateral end of the spine is the acromion,
  where the scapula articulates with the clavicle

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• The glenoid cavity is a depression inferior to
  the acromion. It articulates with the humerus
  head to form the shoulder joint.
• The coracoid process is where muscles attach.

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Upper Limb
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Upper Limb

• Consists of 30 bones (all paired up)
• Humerus in the arm
• Ulna and radius in the forearm
• 8 carpals, 5 metacarpals, and 14 phalanges in the
  hand

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Humerus

• Longest and largest bone of the upper limb
• Articulates with the scapula at the shoulder and
  both the ulna and radius at the elbow

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Ulna

• Located on the medial side of the forearm (pinky
  side)
• Longer than the radius

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Radius

• Located on the lateral side of the forearm (thumb
  side)

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Humerus Bone Surface Markings

• Proximal end consists of a head that articulates
  with the scapulas glenoid cavity and an
  anatomical neck where the epiphyseal plate used
  to be

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• The body contains the deltoid tuberosity, a
  roughened V-shaped area where the deltoid muscle
  attaches

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• At the distal end, the capitulum articulates with
  the head of the radius.
• The radial fossa is a depression that receives
  the head of the radius when the forearm is bent.

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• The trochlea is a spool-shaped surface that
  articulates with the ulna.
• The coronoid fossa receives part of the ulna when
  the forearm is bent.
• The olecranon fossa is a depression on the back
  of the bone that receives the ulna when the
  forearm is straightened.

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Ulna Bone Surface Markings

• The olecranon forms the prominence of the elbow
  on the proximal end.
• The coronoid process along with the olecranon
  receives the trochlea of the humerus in the
  trochlear notch.

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• The radial notch is a depression for the head of
  the radius.
• A styloid process is at the distal end.

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Radius Bone Surface Markings

• Disc-shaped head at the proximal end articulates
  with the capitulum of the humerus and radial
  notch of the ulna
• Radial tuberosity is a raised, roughened area
  that is where the biceps brachii muscle attaches
  to the bone

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• The distal end of the radius articulates with
  three carpal bones
• Theres a styloid process at the distal end
  (similar to the ulna)

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Carpus (Wrist)

• 8 carpals
• Held together by ligaments with four bones in
  each row
• Named for their shapes
• Short bones

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• The carpals in the top row are the
• Scaphoid, Lunate, Triquetrum, and Pisiform
• The carpals in the bottom row are the
• Trapezium, Trapezoid, Capitate, and Hamate

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Metacarpus (Palm)

• 5 metacarpals
• Each consists of a proximal base, an intermediate
  body, and a distal head
• Numbered I-V starting with the thumb
• Long bones

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Phalanges (Fingers)

• 14 in each hand
• Thumb has two (proximal and distal)
• In each of the other four digits, there are three
  (proximal, middle, and distal)

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Disorders of the Upper Limb
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Carpal Tunnel Syndrome

• Narrowing of the carpal tunnel causes compression
  of the median nerve
• The nerve compression causes pain, numbness,
  tingling, and hand muscle weakness

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Rotator Cuff Injury

• Tears or inflammation of ligaments and tendons of
  the shoulder near the humerus
• Results in pain and loss of shoulder mobility

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Fractures
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Checkpoint Questions

• Which bones make up a pectoral girdle? What is
  the function of the pectoral girdle?
• With which part of the scapula does the humerus
  articulate?
• What part of the ulna is called the elbow?
• What part of which bones are commonly called the
  knuckles?
• What bones form the upper limb, from proximal to
  distal?