Medial pterygoid plate
Encyclopedia
The medial pterygoid plate (or medial pterygoid lamina) of the sphenoid
is narrower and longer than the lateral pterygoid plate
; it curves lateralward at its lower extremity into a hook-like process, the pterygoid hamulus
, around which the tendon of the Tensor veli palatini glides.
The lateral surface of this plate forms part of the pterygoid fossa
, the medial surface constitutes the lateral boundary of the choana
or posterior aperture of the corresponding nasal cavity.
Superiorly the medial plate is prolonged on to the under surface of the body as a thin lamina, named the vaginal process, which articulates in front with the sphenoidal process of the palatine and behind this with the ala of the vomer
.
The angular prominence between the posterior margin of the vaginal process and the medial border of the scaphoid fossa
is named the pterygoid tubercle, and immediately above this is the posterior opening of the pterygoid canal
.
On the under surface of the vaginal process is a furrow, which is converted into a canal by the sphenoidal process of the palatine bone
, for the transmission of the pharyngeal branch of the internal maxillary artery
and the pharyngeal nerve from the sphenopalatine ganglion.
The pharyngeal aponeurosis is attached to the entire length of the posterior edge of the medial plate, and the Constrictor pharyngis superior takes origin from its lower third.
Projecting backward from near the middle of the posterior edge of this plate is an angular process, the processus tubarius, which supports the pharyngeal end of the auditory tube.
The anterior margin of the plate articulates with the posterior border of the vertical part of the palatine bone.
Sphenoid bone
The sphenoid bone is an unpaired bone situated at the base of the skull in front of the temporal bone and basilar part of the occipital bone.The sphenoid bone is one of the seven bones that articulate to form the orbit...
is narrower and longer than the lateral pterygoid plate
Lateral pterygoid plate
The lateral pterygoid plate of the sphenoid is broad, thin, and everted; its lateral surface forms part of the medial wall of the infratemporal fossa, and gives attachment to the lateral pterygoid muscle; its medial surface forms part of the pterygoid fossa, and gives attachment to the medial...
; it curves lateralward at its lower extremity into a hook-like process, the pterygoid hamulus
Pterygoid hamulus
The medial pterygoid plate of the sphenoid curves laterally at its lower extremity into a hook-like process, the pterygoid hamulus, around which the tendon of the Tensor veli palatini glides.-External links: *...
, around which the tendon of the Tensor veli palatini glides.
The lateral surface of this plate forms part of the pterygoid fossa
Pterygoid fossa
The pterygoid fossa is an anatomical term for the fossa formed by the divergence of the lateral pterygoid plate and the medial pterygoid plate of the sphenoid bone.-Structure:...
, the medial surface constitutes the lateral boundary of the choana
Choana
Choana is the posterior nasal aperture.The choanae are separated by the vomer.- Boundaries :It is the opening between the nasal cavity and the nasopharynx....
or posterior aperture of the corresponding nasal cavity.
Superiorly the medial plate is prolonged on to the under surface of the body as a thin lamina, named the vaginal process, which articulates in front with the sphenoidal process of the palatine and behind this with the ala of the vomer
Vomer
The vomer is one of the unpaired facial bones of the skull. It is located in the midsagittal line, and articulates with the sphenoid, the ethmoid, the left and right palatine bones, and the left and right maxillary bones.-Biology:...
.
The angular prominence between the posterior margin of the vaginal process and the medial border of the scaphoid fossa
Scaphoid fossa
In the pterygoid processes of the sphenoid, above the pterygoid fossa is a small, oval, shallow depression, the scaphoid fossa, which gives origin to the Tensor veli palatini.-External links:*...
is named the pterygoid tubercle, and immediately above this is the posterior opening of the pterygoid canal
Pterygoid canal
The pterygoid canal is a passage in the skull leading from just anterior to the foramen lacerum in the middle cranial fossa to the pterygopalatine fossa.-Structure:...
.
On the under surface of the vaginal process is a furrow, which is converted into a canal by the sphenoidal process of the palatine bone
Palatine bone
The palatine bone is a bone in many species of the animal kingdom, commonly termed the palatum .-Human anatomy:...
, for the transmission of the pharyngeal branch of the internal maxillary artery
Internal maxillary artery
The maxillary artery is an artery that supplies deep structures of the face. It branches from the external carotid artery just deep to the neck of the mandible.-Structure:...
and the pharyngeal nerve from the sphenopalatine ganglion.
The pharyngeal aponeurosis is attached to the entire length of the posterior edge of the medial plate, and the Constrictor pharyngis superior takes origin from its lower third.
Projecting backward from near the middle of the posterior edge of this plate is an angular process, the processus tubarius, which supports the pharyngeal end of the auditory tube.
The anterior margin of the plate articulates with the posterior border of the vertical part of the palatine bone.