The Appendicular Skeleton
consists of : -
Shoulder girdle with the upper limbs
Pelvic girdle with the lower limbs
Shoulder girdle and upper limb
1 clavicle
1 scapula
1 humerus
1 radius
1 ulna
8 carpals bones
5 metacarpals
14 phalanges
Clavicle
Long
Double curve
Articulates with manubrium sterni - sternoclavicular joint
Articulates with acromion process of the scapula - acromioclavicular joint.
Clavicle the only bony link to axial skeleton for the upper limb
Scapula
Flat - triangular
On the posterior chest
Superficial to the ribs
Separated from them by muscles
Glenoid cavity + head of humerus = shoulder joint.
Posteriorly - spine of scapula
Acromion + clavicle - Acromioclavicular joint
Coracoid process gives attachments to muscles of the shoulder
Supraspinatus fossa - origin of supraspinatus muscle
Infraspinatus fossa - origin of infraspinatus muscle
Humerus
Upper arm bone
Head + glenoid cavity of scapula = shoulder joint
Greater and lesser tubercles
Between the tubercle there is a deep groove - bicipital groove
Deltoid tuberosity- on the lateral surface of the humerus - the deltoid muscle
Distal end two surfaces - trochlea and capitulum- articulate with the ulna and radius
Lateral and medial epicondyles
Medial supracondylar ridge -
lateral supracondylar ridge.- coronoid fossa.
Radius
Lateral bone of the forearm
Parts :
Head
Neck
Radial tuberosity
Shaft
Upper end articulates with the ulna - proximal radioulnar joint
Lower end articulates with the carpal bones to form wrist joint.
Styloid process - a sharp process at the lower end.
Ulna
The medial bone of the forearm
Upper end articulates with humerus to form elbow joint
At the lower end articulates with radius = inferior radioulnar joints
Interosseous membrane holds ulna with the radius
The other parts are Trochlear notch - coronoid process - shaft of ulna - ulnar styloid
Carpal Bones
Closely fitted together by ligaments
Proximal row wrist joint with radius
Tendons and muscles lying in the forearm cross the wrist and are held close to the bones by strong fibrous bands called retinacula - flexor and extensor retinacula
Metacarpal Bones
5 in number - form palm - proximal ends articulate with the carpal bones and the distal ends with the phalanges.
Phalanges
14 phalanges - two in the thumb - 3 in the others - Metacarpo-phalangeal joints- proximal interphalangeal joints - distal interphalangeal joints.
Pelvic girdle and lower limb
Bones of the pelvic girdle
2 hip bones and 1 sacrum
the bones of the lower extremity are:-
1 femur
1 tibia
1 fibula
1patella
7 tarsal bones
5 metatarsal bones
14 phalanges
Hip bones
Three fused bones - the ilium, ischium and pubis
The pit formed by all the three - acetabulum hip joint with head of femur.
Ilium : flattened bone
The parts are - iliac crest - anterior superior iliac spine -
Pubis anterior part of the bone: articulates with the pubis of the other hip bone → cartilagenous joint, the symphysis pubis.
Ischium is the inferior and posterior part.
The pelvis
Pelvis is formed by two hip bones.
Anteriorly symphysis pubis
Posteriorly articulates with the sacrum at the sacroiliac joints
Divided into two parts by the brim of the pelvis, promontaory of the sacrum , iliopectineal lines of the hip bones
Greater or false pelvis above the brim and the lesser or true pelvis below.
Femur
Longest and strongest bone
Head - spherical - articulates at acetabulum - hip joint
Depression in head for ligament of the head of the femur - contains blood vessel - ligamentum teres
Neck - most of the neck within the capsule of the hip joint
posterior surface called linea aspera - gives attachments to muscles
Popliteal surface
Distally two articular condyles - articulate with tibia and fibula to form the knee joint
Tibia
Leg bone
Situated medially
Two condyles at the upper end; lateral and medial condyles - form knee joint with femur
Inferior aspect of the lateral condyle articulates with the head of the fibula, forming the superior tibiofibular joint.
Distal end articulates with the talus - ankle joint; and the fibula - inferior tibiofibular joint
The elongated process called at the inferior end : Medial malleolus
Fibula
Long slender Lateral bone of the leg.
Head articulates with the lateral condyle of the tibia - superior tibiofibular joint
Lower extremity articulates with the tibia then projects beyond it to form the lateral malleolus.
The medial aspect of the lower end articulates with the tibia to form the inferior tibiofibular joint
Patella
Triangular
Sesamoid bone
In front of knee joint
Posterior surface articulates with the patellar surface of the femur in the knee joint
Its anterior surface is embedded in quadriceps femoris tendon
Tarsal bones
Seven -
1 talus
1 calcaneus
1 navicular
3 cuneiforms
1 cuboid
The talus articulates with the tibia and fibula at the ankle joint
The other bones articulate with each other and with metatarsal bones.
Metatarsal bones
Five - proximally articulate with the tarsal bones and distally with the phalanges.
Phalanges
14 - form metatarso phalangeal joints and proximal and distal interphalangeal joints.
Arches of the foot
Arrangement of the bones of the foot like a bridge supported by muscles and ligaments - four arches - a medial and lateral longitudinal arch and two transverse arches.
Medial longitudinal arch
Highest arch
Formed by - calcaneus, navicular, three cuneiform and first three metatarsal bones - only the calcaneus and the distal end of the metatarsal bones touch the ground.
Lateral longitudinal arch
Less marked - bony components are the calcaneus, cuboid and the two lateral metatarsal bones.
Transverse arches
Run across the foot and can be more easily seen by examining the skeleton than the live model - most marked at the level of the three cuneiform and cuboid bones.
Muscles and ligaments which support the arches of the foot
Movable joints - hence very strong muscles and ligaments are necessary to maintain the strength, resilience and stability of the foot during walking, running and jumping.
Posterior tibialis muscle
Most important muscular support of the medial longitudinal arch
Originates from the middle third of the tibia and fibula posteriorly
Its tendon passes behind the medial malleolus
Inserted into the navicular, cuneiform, cuboid and metatarssal bones.
Forms a sling or suspension apparatus for the arch.
Short muscles of the foot
This group of muscles is mainly concerned with the maintenance of the lateral longitudinal and transverse arches - they make up the fleshy part of the sole of the foot.
