APPENDICULAR SKELETON
Chapter 9

(Note: most of this material will be covered in lab)
Pectoral Girdle & Upper Extremity.
Pelvic Girdle and Lower Extremity.

Pectoral Girdle & Upper Extremity


Pectoral girdle = 2 scapulae + 2 clavicles. Provides for muscular attachments that move the arm.

Clavicle (a.k.a., collarbone)
S-shaped. Links scapula to axial skeleton. Protects brachial plexus.
Acromial and sternal ends--sternoclavicular and acromioclavicular joints.
Conoid tuberosity or tubercle (coracoclavicular ligament attachment).
Commonly broken, especially in bicyclists.

Scapula (aka the shoulder blade). Triangular, flat bone posterior to rib cage (overlies ribs 2-7).
15 muscles attach to the scapula.
Spine on posterior surface with acromion process; also divides posterior surface into supraspinous fossa and infraspinous fossa.
Subscapular fossa on anterior surface.
Coracoid process -- muscle attachment site.
Glenoid cavity for head of humerus. Shallow ball-and-socket joint.

3 borders:

  1. superior
  2. medial (vertebral)
  3. lateral (axillary)


Two angles: superior and inferior. (the "missing" angle is the glenoid fossa).

Shoulder Anatomy

Shoulder Anatomy -- mini-tutorial

Brachium: or upper arm.

Humerus: (note -- it's not spelled humorous!!!!)
Proximal end: Head articulates with scapula at glenoid cavity.
Greater and lesser tubercles near head for muscle attachments.
Intertubercular groove for biceps tendon.
Shaft with deltoid tuberosity for attachment of deltoid muscle.

Distal end: trochlea (pulley) and capitulum.
Trochlea articulates with ulna, capitulum articulates with radius.
Coronoid fossa on anterior end, olecranon fossa on posterior end.
Lateral and medial epicondyles are sites of muscle attachments.
Ulnar nerve passes through ‘cubital tunnel" created by medial epicondyle.
"Tennis elbow" is clinically known as lateral epicondylitis.
"Golfer’s elbow" is clinically known as medial epicondylitis.

Antebrachium (forearm): 2 bones--ulna and radius, both are long bones.
Ulna--medial; Radius--lateral

Ulna
Proximal end: articulates with humerus and radius.
Olecranon process, or elbow, articulates with trochlea at semilunar notch.
Coronoid process articulates with head of radius.

Shaft: Interosseous crest for ligament attachment to radius.
Distal end: small, head has styloid process (medial portion of wrist).

Radius
Proximal end: small. Head articulates with ulna.
Shaft: upper end has radial tuberosity for attachment to biceps.
Distal end: relatively large, Lateral styloid process--at wrist.
Articulates with scaphoid (navicular) and lunate bones of wrist.

Supination and pronation of forearm made possible by radius rotating across the ulna.

Carpals: Bones of the wrist.
2 rows of 4 bones each. Cuboidal bones.
Proximal Row: Scaphoid (navicular), lunate, triquetrum, pisiform
Distal Row: Trapezium, trapezoid, capitate, hamate.
The trapezium is important for thumb movement (opposable thumb)
The scaphoid is the most commonly fractured carpal.
Pisiform is a sesamoid bone.
(Dislocation of pisiform)

Metacarpals: 5 bones of the palmar area.
Small long bones. Base interfaces with carpals; shaft; head form knuckles.
I - V numbering system.

Phalanges: (Phalanx is singular) finger bones.
14 in all. 2.3.3.3.3.. Thumb only has 2 phalanges.
Divided into proximal, middle and distal phalanges.

Hand Anatomy Links:
General
Overview
Roentgen’s first published X-ray image of his wife’s hand



PELVIC GIRDLE AND LOWER EXTREMITY

Functions:
Support and Locomotion

Pelvic Girdle or Pelvis(anterior, posterior)= 2 ossa coxae (hipbones).
Linked to sacrum posteriorly at sacroiliac articulation.
Linked anteriorly at symphysis pubis. Fibrocartilage.

Functions:
Supports vertebral column and keeps body upright.
Supports and protects lower viscera.
Attachment for legs (femur) -- transfers weight to femur.
Forms pelvic canal.

Each os coxa has an Ilium, Ischium and Pubis. Begin as separate bones which fuse in the adult.
Acetabulum = depression formed at junction of 3 bones above, site for articulation with head of femur.

Ilium:
Largest and uppermost bone of os coxa.
Iliac crest--site for muscle attachments. Many postural muscles attach here.
2 spinous processes on anterior and posterior surfaces.

Ischium:
Lowest and strongest of pelvic bones. Ischial tuberosity bears weight of body in sitting position.

Pubis:
Anterior projecting bone. Left and right pubis are joined via symphysis pubis--a semi-moveable (amphiarthrosis) joint. Superior ramus meets ilium at acetabulum, inferior ramus meets ischium via the ramus of the ischium.

Obturator Foramen: Passageway for nerves and vessels, formed by rami of pubis and ischium.

Male Vs Female Pelvic Girdles

Adaptations are related to carrying and delivering fetus.
Female pelvis is somewhat smaller -- muscles that attach are smaller. Hips are wider and shallower than males.
"True pelvis" opening is larger in females.
Ischial tuberosity is turned more laterally in females, resulting in wider pubic arch (pubic arch in males is about 90 degrees, in females the arch is greater than 90 degrees -- the easiest feature to identify).

Other differences are found in:

Shape of pelvic inlet and obturator foramen
Length and depth of symphysis pubis.
Orientation of acetabulum

Lower Extremity

Femur:
Long bone. Only bone of thigh (da thighbone's connected to .....).
The longest, heaviest and strongest bone in the body. A person's height is generally 4X femur length.
Proximal head which articulates with hipbone at acetabulum. Greater and lesser trochanters are large tuberosities for muscle attachment (thigh and buttock muscles attach.
Shaft: linea aspera -- site of muscle insertion.
Distal end: Medial and lateral condyles articulate with tibia and patella. Lateral and medial epicondyles provide ligament attachments. Anterior surface has flattened region for interface of patella (patellar surface).

Patella or kneecap

A sesamoid bone: within the quadriceps femoris tendon. Protects knee and allows for more leverage for quads. Triangular bone with upper base and lower apex. Posterior facets for articulation with condyles of femur.

Lower Leg: Tibia (medial) and Fibula (lateral)

Tibia = shinbone.
A long bone. Similar to femur in length, strength and density. Supports weight and transfers force to foot (talus).
Proximal end: Lateral and medial condyles which articulate with lateral and medial condyles of femur.
Tibial tuberosity for patellar ligament attachment. Articulation with head of fibula.
Shaft: anterior crest.
Distal end: expanded in the form of medial malleolus. Articulation with talus of foot. Articulation with fibula.

Note: stress fractures of tibia can feel like a "shinsplint," but are distinctly different.

Fibula:
parallels tibia, but much thinner. For muscle attachment, little weight bearing role.
Proximal = head, which articulates with tibia.
Shaft = long and thin--no remarkable features.
Distal = has lateral malleolus.
The fibula is often used for transplantation -- serves as graft to replace damaged long bones (other source on grafting)

Ankle and Foot:
Tarsus (7 bones) , Metatarsus (5 bones) and Phalanges (14 bones) per leg.
Tarsus: 7 short or cuboidal bones.
Talus: articulates with tibia to form ankle joint. Distributes force of upper leg to foot.
Calcaneus: heel bone. largest tarsal bone. Receives 1/2 of force from talus.
Site of ligament attachment (calf muscles).
Navicular, cuboid and 3 cuneiforms make up rest of tarsus.

Metatarsals: Form sole of foot. 1 bone per toe.
Small, long bones with base (tarsal interface), shaft, and head (phalanges interface).
Numbered 1-5 medial to lateral.

Phalanges: bones that make up toes. Numbering system as for hand.
Phalanges are similar to those of hand, just shorter and thicker.
Big toe is not opposable.

Arches of feet: Longitudinal and transverse curves formed by angle between tarsals and metatarsals.
Provide support and leverage for walking. Bones are held together by ligaments which provide "spring" in step.
Weakened ligaments result in "fallen arches" or "flat feet."


Normal Growth and development of skeleton with emphasis on appendicular skeleton

Developmental Conditions of Appendicular Skeleton

Syndactyly: Genetic. Webbed digits
Polydactyly: Genetic. Extra digits present (fingers or toes)
Clubfoot (talipes): congenital condition in which foot is twisted medially. (Personal Case History)




Misc Links

LUMEN's Bone Box
General Skeletal Anatomy Links
Summary Bone tables

Treating tennis elbow with anti-oxidants and fatty acids