A fossa is a depression or hollow area in a bone. Fossae (plural) can vary in size and shape, and they serve various functions, such as providing space for muscle attachment, housing structures like nerves and blood vessels, or forming part of a joint. Fossae are found throughout the skeletal system and are essential for the proper functioning of the musculoskeletal and nervous systems.
Location and Examples of Fossae
Cranial Fossae
Anterior Cranial Fossa
- Location: This fossa is located at the front of the skull base, formed by the frontal bone, ethmoid bone, and part of the sphenoid bone.
- Function: It supports the frontal lobes of the brain.
Middle Cranial Fossa
- Location: Positioned centrally at the skull base, it is formed by the sphenoid and temporal bones.
- Function: This fossa houses the temporal lobes of the brain and the pituitary gland.
Posterior Cranial Fossa
- Location: Found at the back of the skull base, formed by the occipital bone and parts of the temporal and parietal bones.
- Function: It contains the cerebellum, pons, and medulla oblongata.
Facial Fossae
Temporal Fossa
- Location: Located on the side of the skull, formed by parts of the temporal, parietal, frontal, and sphenoid bones.
- Function: It provides space for the temporalis muscle, which is involved in chewing.
Infratemporal Fossa
- Location: Situated below the temporal fossa and deep to the ramus of the mandible.
- Function: Contains muscles of mastication, blood vessels, and nerves.
Pterygopalatine Fossa
- Location: Found deep within the skull, between the pterygoid process of the sphenoid bone and the maxilla.
- Function: Houses the pterygopalatine ganglion and various neurovascular structures.
Thoracic and Abdominal Fossae
Supraspinous Fossa
- Location: Located above the spine on the posterior surface of the scapula.
- Function: Serves as the origin for the supraspinatus muscle, part of the rotator cuff.
Infraspinous Fossa
- Location: Found below the spine on the posterior surface of the scapula.
- Function: Serves as the origin for the infraspinatus muscle, another part of the rotator cuff.
Subscapular Fossa
- Location: Located on the anterior surface of the scapula.
- Function: Provides the origin for the subscapularis muscle, part of the rotator cuff.
Iliac Fossa
- Location: A large, concave surface on the internal aspect of the ilium, part of the pelvic bone.
- Function: It provides the origin for the iliacus muscle, which is involved in hip flexion.
Joint Fossae
Glenoid Fossa
- Location: A shallow depression in the scapula that articulates with the head of the humerus to form the shoulder joint.
- Function: It allows for a wide range of shoulder movements.
Acetabular Fossa
- Location: A deep socket in the pelvis that articulates with the head of the femur to form the hip joint.
- Function: Provides stability and support for the hip joint, allowing for weight-bearing and movement.
