Joints and Postcranium Practice Flashcards

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Axial skeleton

Back

The central framework of the skeleton, including the skull, vertebral column, and thoracic cage (ribs and sternum). It provides support for the body's axis, protects the brain and thoracic organs, and serves as a site for muscle attachment.

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Appendicular skeleton

Back

Bones of the limbs and girdles, including the pectoral girdle (scapula and clavicle) and pelvic girdle (os coxae). It comprises the upper and lower limbs, including the humerus, radius, ulna, femur, tibia, fibula, carpals, metacarpals, and phalanges.

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Joints

Back

Articulations where two or more bones meet. They range from immovable to highly mobile, enabling diverse movements. Movement is produced by muscles across joints and stabilized by ligaments and the joint capsule.

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Synovial joints

Back

Joints that have a fluid-filled synovial cavity and are typically highly mobile. They are enclosed by a joint capsule with fibrous and synovial layers and have hyaline cartilage at articular surfaces. Stability comes from ligaments and surrounding soft tissues.

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Fibrous joints

Back

Joints bound by dense collagen fibers; little to no movement and no true joint cavity. Examples include sutures, gomphoses, and syndesmoses.

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Cartilaginous joints

Back

Joints where bones are joined by cartilage tissue (hyaline or fibrocartilage); they allow limited movement and lack a joint cavity. Examples include intervertebral discs and the pubic symphysis.

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Ball and socket joints

Back

Joints with a spherical head fitting into a rounded socket, allowing movement in three planes. Examples include the hip (coxal) and shoulder (glenohumeral) joints.

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Hinge joints

Back

Joints in which a cylindrical end fits into a trough, permitting angular movement in one plane (flexion/extension). Examples include the elbow and interphalangeal joints.

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Pivot joints

Back

Joints where rotation occurs around a bone's long axis. Examples include the radioulnar joints and the atlanto-axial joint, enabling forearm and head rotation (pronation/supination and nodding).

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Saddle joints

Back

Joints with concave and convex articular surfaces that allow biaxial motion. Classic example is the carpometacarpal joint of the thumb (pollex) and the sternoclavicular joint.

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Condyloid joints

Back

Ellipsoid joints permitting flexion/extension and abduction/adduction in two planes. Examples include the metacarpophalangeal joints and the wrist.

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Plane joints

Back

Joints with flat articular surfaces that allow gliding/sliding movements and some rotation. Found in intercarpal/tarsal joints and zygapophyseal joints between vertebrae.

Front

Glenohumeral joint

Back

Shoulder joint formed by the articulation of the humeral head with the glenoid fossa of the scapula. It is highly mobile (ball-in-socket) and stabilized by the glenoid labrum, rotator cuff muscles, and ligaments.

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Knee joint

Back

The largest, most complex joint, comprising the tibiofemoral and patellofemoral joints. It functions mainly as a hinge but allows some rotation in flexion; stability is provided by ligaments and menisci, including the ACL and PCL.

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Ankle joint

Back

A hinge joint formed by the tibia, fibula, and talus, enabling dorsiflexion and plantar flexion. The mortise formed by tibia and fibula provides stability via ligaments.

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Vertebral column

Back

The spine is divided into cervical (7), thoracic (12), lumbar (5), sacral (5 fused), and coccygeal (3–5 fused) regions. It protects the spinal cord, supports body weight, and provides rigidity and flexibility for the torso.

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Intervertebral discs

Back

Cartilaginous discs between adjacent vertebrae consisting of an outer annulus fibrosus and a gel-like nucleus pulposus. They cushion load and permit limited vertebral movement.

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Ribs

Back

Twelve pairs forming the thoracic cage; posteriorly articulating with thoracic vertebrae and anteriorly with the sternum or its cartilages. True ribs are 1–7, false ribs are 8–10, and floating ribs are 11–12.

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Os coxae

Back

The hip bone, composed of ilium, ischium, and pubis, which fuse in adolescence. It articulates with the sacrum at the sacroiliac joint and with the femur at the acetabulum.

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Acetabulum

Back

The acetabulum is the socket of the hip joint on the os coxae that receives the femoral head. The acetabular labrum deepens the socket and ligaments contribute to stability.

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Sternum

Back

The sternum (breastbone) consists of the manubrium, corpus (body), and xyphoid process. It articulates with the clavicles at the sternoclavicular joints and with the first seven ribs at the costosternal joints; the sternal angle marks the junction between manubrium and body.

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Arches of the foot

Back

The human foot is arched to support efficient bipedal locomotion. It contains three arches: the medial longitudinal, the lateral longitudinal, and the transverse arch, which distribute weight and absorb shocks.